Mongodb change the order of an array
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I am stumped on this one. I have an images array with in my collection, the users can rearrange the order of images on the client side and I am trying to save the new order to the database. The imagesOrder array is the new images in the new order and it only has the url so I want to match the url to the urls in the database. I am not sure how to make the index a variable or if this is possible:
this is what I have so far. my code editor shows and error on [index] so I know that is not the proper format but not sure what is:
imagesOrder.forEach((index, image) => {
const imageUrl = image.url
const index = index
Users.update({
id
}, {
$set: {
images[index]: imageUrl
}
})
});
javascript mongodb
add a comment |
up vote
0
down vote
favorite
I am stumped on this one. I have an images array with in my collection, the users can rearrange the order of images on the client side and I am trying to save the new order to the database. The imagesOrder array is the new images in the new order and it only has the url so I want to match the url to the urls in the database. I am not sure how to make the index a variable or if this is possible:
this is what I have so far. my code editor shows and error on [index] so I know that is not the proper format but not sure what is:
imagesOrder.forEach((index, image) => {
const imageUrl = image.url
const index = index
Users.update({
id
}, {
$set: {
images[index]: imageUrl
}
})
});
javascript mongodb
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I am stumped on this one. I have an images array with in my collection, the users can rearrange the order of images on the client side and I am trying to save the new order to the database. The imagesOrder array is the new images in the new order and it only has the url so I want to match the url to the urls in the database. I am not sure how to make the index a variable or if this is possible:
this is what I have so far. my code editor shows and error on [index] so I know that is not the proper format but not sure what is:
imagesOrder.forEach((index, image) => {
const imageUrl = image.url
const index = index
Users.update({
id
}, {
$set: {
images[index]: imageUrl
}
})
});
javascript mongodb
I am stumped on this one. I have an images array with in my collection, the users can rearrange the order of images on the client side and I am trying to save the new order to the database. The imagesOrder array is the new images in the new order and it only has the url so I want to match the url to the urls in the database. I am not sure how to make the index a variable or if this is possible:
this is what I have so far. my code editor shows and error on [index] so I know that is not the proper format but not sure what is:
imagesOrder.forEach((index, image) => {
const imageUrl = image.url
const index = index
Users.update({
id
}, {
$set: {
images[index]: imageUrl
}
})
});
javascript mongodb
javascript mongodb
asked Nov 21 at 23:55
Kris
9110
9110
add a comment |
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
accepted
So that is not actually the way you would do this. Basically there is no need to actually send an update request to the server for every single indexed position for the array. Also the update()
method is asynchronous, so it's not something you ever put inside a forEach()
which does not respect awaiting the completion of an asynchronous call.
Instead what is usually the most practical solution is to just $set
the entire array content in one request. Also mocking up your imagesOrder
to something practical since forEach()
even actually has the signature of .forEach((<element>,><index>) => ...
, which seems different to what you were expecting given the code in the question.
var imagesOrder = [
{ index: 0, url: '/one' }, { index: 1, url: '/two' }, { index: 2, url: '/three' }
];
let response = await Users.updateOne(
{ id },
{ "$set": { "images": imagesOrder.map(({ url }) => url) } }
);
// { "$set": { "images": ["/one","/two","/three"] } }
Much like the forEach()
a map()
does the same array iteration but with the difference that it actually returns an array generated by the processing function. This is actually what you want since all that is needed here is to simply extract the values of the url
property from each object.
Note the index
properties are actually already in order and really redundant here, but I'm just approximating what it sounds like you have from your question. Since an "array" actually maintains it's own order then such a property "should" be redundant and it would be advisable that your source array data actually conforms to this.
If however you managed to record such index
values in a way they are actually out of order, then the best solution is to add a sort()
:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
let response = await Users.updateOne(
{ id },
{ "$set": {
"images": imagesOrder.sort((a,b) => a.index - b.index)
.map(({ url }) => url)
}}
);
// { "$set": { "images": ["/one","/two","/three"] } }
As for what you "attempted", it's not really benefiting you in any way to actually attempt updating each element at a given position. But if you really wanted to see it done, then again you actually would just instead build up a single update request:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
var update = { $set: {} };
for ( let { url, index } of imagesOrder.sort((a,b) => a.index - b.index) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
Or in the case where the index
property was not there or irrelevant since the array is already ordered:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
for ( let [index, { url }] of Object.entries(imagesOrder) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
So it's all pretty much the same thing. Note the common form of notation is actually a "string" for the key which includes the index position numerically. This is described in Dot Notation within the core documentation for the MongoDB query language.
The one main difference here is that should your new array contain more entries than the actual array stored in the document to be modified, that second form using the "dot notation" to the indexed position is going to fail since it cannot "set" an index position which does not exist.
For this reason even though there are other pitfalls to "replacing" the array as the original examples show, it's a lot safer than attempting to update via the positional index in the stored document.
Note that this should be enough to have you at least started in the right direction. Making this work with multiple users possibly updating the data at once can become pretty complicated in terms of update statements for both checking and merging changes.
In most cases the simple "replace" will be more than adequate at least for a while. And of course the main lesson here should be to not loop "async" methods in places where it is completely unnecessary. Most of the time what you really want to "loop" is the construction of the statement, if of course any looping is required at all and most of the time it really isn't.
Addendum
Just in case you or anyone had it in mind to actually store an array of objects with the index
position values stored within them, this can become a little more complex, but it can also serve as an example of how to actually issue an update statement which does not "replace" the array and actually is safe considering it does not rely on indexed positions of the array but instead using matching conditions.
This is possible with the positional filtered $[<identifier>]
syntax introduced in MongoDB 3.6. This allows conditions to specify which element to update ( i.e by matching url ) instead of including the index positions within the statement directly. It's safer since if no matching element is found, then the syntax allows for not attempting to change anything at all.
Also as demonstration the method to $sort
the elements based on updated index
values is shown. Noting this actually uses the $push
modifier even though in this statement we are not actually adding anything to the array. Just reordering the elements. But it's how you actually do that atomically:
const { Schema, Types: { ObjectId } } = mongoose = require('mongoose');
const uri = 'mongodb://localhost:27017/longorder';
const opts = { useNewUrlParser: true };
// sensible defaults
mongoose.Promise = global.Promise;
mongoose.set('debug', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
// schema defs
const imageSchema = new Schema({
index: Number,
url: String
})
const userSchema = new Schema({
images: [imageSchema]
});
const User = mongoose.model('User', userSchema);
// log helper
const log = data => console.log(JSON.stringify(data, undefined, 2));
(async function() {
try {
const conn = await mongoose.connect(uri, opts);
// clean models
await Promise.all(
Object.entries(conn.models).map(([k,m]) => m.deleteMany())
);
// Create data
let _id = new ObjectId();
let user = await User.findOneAndUpdate(
{ _id },
{
'$push': {
'images': {
'$each': [
{ index: 2, url: '/one' },
{ index: 0, url: '/three' },
{ index: 1, url: '/two' }
],
'$sort': { 'index': 1 }
}
}
},
{ 'new': true, 'upsert': true }
);
log(user);
// Change order request
let orderImages = [
{ index: 2, url: '/three' },
{ index: 0, url: '/one' },
{ index: 1, url: '/two' }
];
let $set = { };
let arrayFilters = ;
for ( { index, url } of orderImages ) {
let key = url.replace(/^//,'');
arrayFilters.push({ [`${key}.url`]: url });
$set[`images.$[${key}].index`] = index;
}
let ops = [
// Update the index value of each matching item
{ 'updateOne': {
'filter': { _id },
'update': { $set },
arrayFilters
}},
// Re-sort the array by index value
{ 'updateOne': {
'filter': { _id },
'update': {
'$push': {
'images': { '$each': , '$sort': { 'index': 1 } }
}
}
}}
];
log(ops);
let response = await User.bulkWrite(ops);
log(response);
let newuser = await User.findOne({ _id });
log(newuser);
} catch(e) {
console.error(e)
} finally {
mongoose.disconnect()
}
})()
And the output, showing initial document state, the update and actual changes made:
Mongoose: users.deleteMany({}, {})
Mongoose: users.findOneAndUpdate({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { '$setOnInsert': { __v: 0 }, '$push': { images: { '$each': [ { _id: ObjectId("5bf6116621293f2ab3dec3d6"), index: 2, url: '/one' }, { _id: ObjectId("5bf6116621293f2ab3dec3d5"), index: 0, url: '/three' }, { _id: ObjectId("5bf6116621293f2ab3dec3d4"), index: 1, url: '/two' } ], '$sort': { index: 1 } } } }, { upsert: true, remove: false, projection: {}, returnOriginal: false })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 0,
"url": "/three"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 2,
"url": "/one"
}
]
}
[
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$set": {
"images.$[three].index": 2,
"images.$[one].index": 0,
"images.$[two].index": 1
}
},
"arrayFilters": [
{
"three.url": "/three"
},
{
"one.url": "/one"
},
{
"two.url": "/two"
}
]
}
},
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$push": {
"images": {
"$each": ,
"$sort": {
"index": 1
}
}
}
}
}
}
]
Mongoose: users.bulkWrite([ { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$set': { 'images.$[three].index': 2, 'images.$[one].index': 0, 'images.$[two].index': 1 } }, arrayFilters: [ { 'three.url': '/three' }, { 'one.url': '/one' }, { 'two.url': '/two' } ] } }, { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$push': { images: { '$each': , '$sort': { index: 1 } } } } } } ], {})
{
"ok": 1,
"writeErrors": ,
"writeConcernErrors": ,
"insertedIds": ,
"nInserted": 0,
"nUpserted": 0,
"nMatched": 2,
"nModified": 2,
"nRemoved": 0,
"upserted": ,
"lastOp": {
"ts": "6626503031506599940",
"t": 139
}
}
Mongoose: users.findOne({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { projection: {} })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 0,
"url": "/one"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 2,
"url": "/three"
}
]
}
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
So that is not actually the way you would do this. Basically there is no need to actually send an update request to the server for every single indexed position for the array. Also the update()
method is asynchronous, so it's not something you ever put inside a forEach()
which does not respect awaiting the completion of an asynchronous call.
Instead what is usually the most practical solution is to just $set
the entire array content in one request. Also mocking up your imagesOrder
to something practical since forEach()
even actually has the signature of .forEach((<element>,><index>) => ...
, which seems different to what you were expecting given the code in the question.
var imagesOrder = [
{ index: 0, url: '/one' }, { index: 1, url: '/two' }, { index: 2, url: '/three' }
];
let response = await Users.updateOne(
{ id },
{ "$set": { "images": imagesOrder.map(({ url }) => url) } }
);
// { "$set": { "images": ["/one","/two","/three"] } }
Much like the forEach()
a map()
does the same array iteration but with the difference that it actually returns an array generated by the processing function. This is actually what you want since all that is needed here is to simply extract the values of the url
property from each object.
Note the index
properties are actually already in order and really redundant here, but I'm just approximating what it sounds like you have from your question. Since an "array" actually maintains it's own order then such a property "should" be redundant and it would be advisable that your source array data actually conforms to this.
If however you managed to record such index
values in a way they are actually out of order, then the best solution is to add a sort()
:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
let response = await Users.updateOne(
{ id },
{ "$set": {
"images": imagesOrder.sort((a,b) => a.index - b.index)
.map(({ url }) => url)
}}
);
// { "$set": { "images": ["/one","/two","/three"] } }
As for what you "attempted", it's not really benefiting you in any way to actually attempt updating each element at a given position. But if you really wanted to see it done, then again you actually would just instead build up a single update request:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
var update = { $set: {} };
for ( let { url, index } of imagesOrder.sort((a,b) => a.index - b.index) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
Or in the case where the index
property was not there or irrelevant since the array is already ordered:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
for ( let [index, { url }] of Object.entries(imagesOrder) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
So it's all pretty much the same thing. Note the common form of notation is actually a "string" for the key which includes the index position numerically. This is described in Dot Notation within the core documentation for the MongoDB query language.
The one main difference here is that should your new array contain more entries than the actual array stored in the document to be modified, that second form using the "dot notation" to the indexed position is going to fail since it cannot "set" an index position which does not exist.
For this reason even though there are other pitfalls to "replacing" the array as the original examples show, it's a lot safer than attempting to update via the positional index in the stored document.
Note that this should be enough to have you at least started in the right direction. Making this work with multiple users possibly updating the data at once can become pretty complicated in terms of update statements for both checking and merging changes.
In most cases the simple "replace" will be more than adequate at least for a while. And of course the main lesson here should be to not loop "async" methods in places where it is completely unnecessary. Most of the time what you really want to "loop" is the construction of the statement, if of course any looping is required at all and most of the time it really isn't.
Addendum
Just in case you or anyone had it in mind to actually store an array of objects with the index
position values stored within them, this can become a little more complex, but it can also serve as an example of how to actually issue an update statement which does not "replace" the array and actually is safe considering it does not rely on indexed positions of the array but instead using matching conditions.
This is possible with the positional filtered $[<identifier>]
syntax introduced in MongoDB 3.6. This allows conditions to specify which element to update ( i.e by matching url ) instead of including the index positions within the statement directly. It's safer since if no matching element is found, then the syntax allows for not attempting to change anything at all.
Also as demonstration the method to $sort
the elements based on updated index
values is shown. Noting this actually uses the $push
modifier even though in this statement we are not actually adding anything to the array. Just reordering the elements. But it's how you actually do that atomically:
const { Schema, Types: { ObjectId } } = mongoose = require('mongoose');
const uri = 'mongodb://localhost:27017/longorder';
const opts = { useNewUrlParser: true };
// sensible defaults
mongoose.Promise = global.Promise;
mongoose.set('debug', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
// schema defs
const imageSchema = new Schema({
index: Number,
url: String
})
const userSchema = new Schema({
images: [imageSchema]
});
const User = mongoose.model('User', userSchema);
// log helper
const log = data => console.log(JSON.stringify(data, undefined, 2));
(async function() {
try {
const conn = await mongoose.connect(uri, opts);
// clean models
await Promise.all(
Object.entries(conn.models).map(([k,m]) => m.deleteMany())
);
// Create data
let _id = new ObjectId();
let user = await User.findOneAndUpdate(
{ _id },
{
'$push': {
'images': {
'$each': [
{ index: 2, url: '/one' },
{ index: 0, url: '/three' },
{ index: 1, url: '/two' }
],
'$sort': { 'index': 1 }
}
}
},
{ 'new': true, 'upsert': true }
);
log(user);
// Change order request
let orderImages = [
{ index: 2, url: '/three' },
{ index: 0, url: '/one' },
{ index: 1, url: '/two' }
];
let $set = { };
let arrayFilters = ;
for ( { index, url } of orderImages ) {
let key = url.replace(/^//,'');
arrayFilters.push({ [`${key}.url`]: url });
$set[`images.$[${key}].index`] = index;
}
let ops = [
// Update the index value of each matching item
{ 'updateOne': {
'filter': { _id },
'update': { $set },
arrayFilters
}},
// Re-sort the array by index value
{ 'updateOne': {
'filter': { _id },
'update': {
'$push': {
'images': { '$each': , '$sort': { 'index': 1 } }
}
}
}}
];
log(ops);
let response = await User.bulkWrite(ops);
log(response);
let newuser = await User.findOne({ _id });
log(newuser);
} catch(e) {
console.error(e)
} finally {
mongoose.disconnect()
}
})()
And the output, showing initial document state, the update and actual changes made:
Mongoose: users.deleteMany({}, {})
Mongoose: users.findOneAndUpdate({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { '$setOnInsert': { __v: 0 }, '$push': { images: { '$each': [ { _id: ObjectId("5bf6116621293f2ab3dec3d6"), index: 2, url: '/one' }, { _id: ObjectId("5bf6116621293f2ab3dec3d5"), index: 0, url: '/three' }, { _id: ObjectId("5bf6116621293f2ab3dec3d4"), index: 1, url: '/two' } ], '$sort': { index: 1 } } } }, { upsert: true, remove: false, projection: {}, returnOriginal: false })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 0,
"url": "/three"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 2,
"url": "/one"
}
]
}
[
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$set": {
"images.$[three].index": 2,
"images.$[one].index": 0,
"images.$[two].index": 1
}
},
"arrayFilters": [
{
"three.url": "/three"
},
{
"one.url": "/one"
},
{
"two.url": "/two"
}
]
}
},
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$push": {
"images": {
"$each": ,
"$sort": {
"index": 1
}
}
}
}
}
}
]
Mongoose: users.bulkWrite([ { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$set': { 'images.$[three].index': 2, 'images.$[one].index': 0, 'images.$[two].index': 1 } }, arrayFilters: [ { 'three.url': '/three' }, { 'one.url': '/one' }, { 'two.url': '/two' } ] } }, { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$push': { images: { '$each': , '$sort': { index: 1 } } } } } } ], {})
{
"ok": 1,
"writeErrors": ,
"writeConcernErrors": ,
"insertedIds": ,
"nInserted": 0,
"nUpserted": 0,
"nMatched": 2,
"nModified": 2,
"nRemoved": 0,
"upserted": ,
"lastOp": {
"ts": "6626503031506599940",
"t": 139
}
}
Mongoose: users.findOne({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { projection: {} })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 0,
"url": "/one"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 2,
"url": "/three"
}
]
}
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
add a comment |
up vote
1
down vote
accepted
So that is not actually the way you would do this. Basically there is no need to actually send an update request to the server for every single indexed position for the array. Also the update()
method is asynchronous, so it's not something you ever put inside a forEach()
which does not respect awaiting the completion of an asynchronous call.
Instead what is usually the most practical solution is to just $set
the entire array content in one request. Also mocking up your imagesOrder
to something practical since forEach()
even actually has the signature of .forEach((<element>,><index>) => ...
, which seems different to what you were expecting given the code in the question.
var imagesOrder = [
{ index: 0, url: '/one' }, { index: 1, url: '/two' }, { index: 2, url: '/three' }
];
let response = await Users.updateOne(
{ id },
{ "$set": { "images": imagesOrder.map(({ url }) => url) } }
);
// { "$set": { "images": ["/one","/two","/three"] } }
Much like the forEach()
a map()
does the same array iteration but with the difference that it actually returns an array generated by the processing function. This is actually what you want since all that is needed here is to simply extract the values of the url
property from each object.
Note the index
properties are actually already in order and really redundant here, but I'm just approximating what it sounds like you have from your question. Since an "array" actually maintains it's own order then such a property "should" be redundant and it would be advisable that your source array data actually conforms to this.
If however you managed to record such index
values in a way they are actually out of order, then the best solution is to add a sort()
:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
let response = await Users.updateOne(
{ id },
{ "$set": {
"images": imagesOrder.sort((a,b) => a.index - b.index)
.map(({ url }) => url)
}}
);
// { "$set": { "images": ["/one","/two","/three"] } }
As for what you "attempted", it's not really benefiting you in any way to actually attempt updating each element at a given position. But if you really wanted to see it done, then again you actually would just instead build up a single update request:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
var update = { $set: {} };
for ( let { url, index } of imagesOrder.sort((a,b) => a.index - b.index) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
Or in the case where the index
property was not there or irrelevant since the array is already ordered:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
for ( let [index, { url }] of Object.entries(imagesOrder) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
So it's all pretty much the same thing. Note the common form of notation is actually a "string" for the key which includes the index position numerically. This is described in Dot Notation within the core documentation for the MongoDB query language.
The one main difference here is that should your new array contain more entries than the actual array stored in the document to be modified, that second form using the "dot notation" to the indexed position is going to fail since it cannot "set" an index position which does not exist.
For this reason even though there are other pitfalls to "replacing" the array as the original examples show, it's a lot safer than attempting to update via the positional index in the stored document.
Note that this should be enough to have you at least started in the right direction. Making this work with multiple users possibly updating the data at once can become pretty complicated in terms of update statements for both checking and merging changes.
In most cases the simple "replace" will be more than adequate at least for a while. And of course the main lesson here should be to not loop "async" methods in places where it is completely unnecessary. Most of the time what you really want to "loop" is the construction of the statement, if of course any looping is required at all and most of the time it really isn't.
Addendum
Just in case you or anyone had it in mind to actually store an array of objects with the index
position values stored within them, this can become a little more complex, but it can also serve as an example of how to actually issue an update statement which does not "replace" the array and actually is safe considering it does not rely on indexed positions of the array but instead using matching conditions.
This is possible with the positional filtered $[<identifier>]
syntax introduced in MongoDB 3.6. This allows conditions to specify which element to update ( i.e by matching url ) instead of including the index positions within the statement directly. It's safer since if no matching element is found, then the syntax allows for not attempting to change anything at all.
Also as demonstration the method to $sort
the elements based on updated index
values is shown. Noting this actually uses the $push
modifier even though in this statement we are not actually adding anything to the array. Just reordering the elements. But it's how you actually do that atomically:
const { Schema, Types: { ObjectId } } = mongoose = require('mongoose');
const uri = 'mongodb://localhost:27017/longorder';
const opts = { useNewUrlParser: true };
// sensible defaults
mongoose.Promise = global.Promise;
mongoose.set('debug', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
// schema defs
const imageSchema = new Schema({
index: Number,
url: String
})
const userSchema = new Schema({
images: [imageSchema]
});
const User = mongoose.model('User', userSchema);
// log helper
const log = data => console.log(JSON.stringify(data, undefined, 2));
(async function() {
try {
const conn = await mongoose.connect(uri, opts);
// clean models
await Promise.all(
Object.entries(conn.models).map(([k,m]) => m.deleteMany())
);
// Create data
let _id = new ObjectId();
let user = await User.findOneAndUpdate(
{ _id },
{
'$push': {
'images': {
'$each': [
{ index: 2, url: '/one' },
{ index: 0, url: '/three' },
{ index: 1, url: '/two' }
],
'$sort': { 'index': 1 }
}
}
},
{ 'new': true, 'upsert': true }
);
log(user);
// Change order request
let orderImages = [
{ index: 2, url: '/three' },
{ index: 0, url: '/one' },
{ index: 1, url: '/two' }
];
let $set = { };
let arrayFilters = ;
for ( { index, url } of orderImages ) {
let key = url.replace(/^//,'');
arrayFilters.push({ [`${key}.url`]: url });
$set[`images.$[${key}].index`] = index;
}
let ops = [
// Update the index value of each matching item
{ 'updateOne': {
'filter': { _id },
'update': { $set },
arrayFilters
}},
// Re-sort the array by index value
{ 'updateOne': {
'filter': { _id },
'update': {
'$push': {
'images': { '$each': , '$sort': { 'index': 1 } }
}
}
}}
];
log(ops);
let response = await User.bulkWrite(ops);
log(response);
let newuser = await User.findOne({ _id });
log(newuser);
} catch(e) {
console.error(e)
} finally {
mongoose.disconnect()
}
})()
And the output, showing initial document state, the update and actual changes made:
Mongoose: users.deleteMany({}, {})
Mongoose: users.findOneAndUpdate({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { '$setOnInsert': { __v: 0 }, '$push': { images: { '$each': [ { _id: ObjectId("5bf6116621293f2ab3dec3d6"), index: 2, url: '/one' }, { _id: ObjectId("5bf6116621293f2ab3dec3d5"), index: 0, url: '/three' }, { _id: ObjectId("5bf6116621293f2ab3dec3d4"), index: 1, url: '/two' } ], '$sort': { index: 1 } } } }, { upsert: true, remove: false, projection: {}, returnOriginal: false })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 0,
"url": "/three"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 2,
"url": "/one"
}
]
}
[
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$set": {
"images.$[three].index": 2,
"images.$[one].index": 0,
"images.$[two].index": 1
}
},
"arrayFilters": [
{
"three.url": "/three"
},
{
"one.url": "/one"
},
{
"two.url": "/two"
}
]
}
},
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$push": {
"images": {
"$each": ,
"$sort": {
"index": 1
}
}
}
}
}
}
]
Mongoose: users.bulkWrite([ { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$set': { 'images.$[three].index': 2, 'images.$[one].index': 0, 'images.$[two].index': 1 } }, arrayFilters: [ { 'three.url': '/three' }, { 'one.url': '/one' }, { 'two.url': '/two' } ] } }, { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$push': { images: { '$each': , '$sort': { index: 1 } } } } } } ], {})
{
"ok": 1,
"writeErrors": ,
"writeConcernErrors": ,
"insertedIds": ,
"nInserted": 0,
"nUpserted": 0,
"nMatched": 2,
"nModified": 2,
"nRemoved": 0,
"upserted": ,
"lastOp": {
"ts": "6626503031506599940",
"t": 139
}
}
Mongoose: users.findOne({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { projection: {} })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 0,
"url": "/one"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 2,
"url": "/three"
}
]
}
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
So that is not actually the way you would do this. Basically there is no need to actually send an update request to the server for every single indexed position for the array. Also the update()
method is asynchronous, so it's not something you ever put inside a forEach()
which does not respect awaiting the completion of an asynchronous call.
Instead what is usually the most practical solution is to just $set
the entire array content in one request. Also mocking up your imagesOrder
to something practical since forEach()
even actually has the signature of .forEach((<element>,><index>) => ...
, which seems different to what you were expecting given the code in the question.
var imagesOrder = [
{ index: 0, url: '/one' }, { index: 1, url: '/two' }, { index: 2, url: '/three' }
];
let response = await Users.updateOne(
{ id },
{ "$set": { "images": imagesOrder.map(({ url }) => url) } }
);
// { "$set": { "images": ["/one","/two","/three"] } }
Much like the forEach()
a map()
does the same array iteration but with the difference that it actually returns an array generated by the processing function. This is actually what you want since all that is needed here is to simply extract the values of the url
property from each object.
Note the index
properties are actually already in order and really redundant here, but I'm just approximating what it sounds like you have from your question. Since an "array" actually maintains it's own order then such a property "should" be redundant and it would be advisable that your source array data actually conforms to this.
If however you managed to record such index
values in a way they are actually out of order, then the best solution is to add a sort()
:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
let response = await Users.updateOne(
{ id },
{ "$set": {
"images": imagesOrder.sort((a,b) => a.index - b.index)
.map(({ url }) => url)
}}
);
// { "$set": { "images": ["/one","/two","/three"] } }
As for what you "attempted", it's not really benefiting you in any way to actually attempt updating each element at a given position. But if you really wanted to see it done, then again you actually would just instead build up a single update request:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
var update = { $set: {} };
for ( let { url, index } of imagesOrder.sort((a,b) => a.index - b.index) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
Or in the case where the index
property was not there or irrelevant since the array is already ordered:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
for ( let [index, { url }] of Object.entries(imagesOrder) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
So it's all pretty much the same thing. Note the common form of notation is actually a "string" for the key which includes the index position numerically. This is described in Dot Notation within the core documentation for the MongoDB query language.
The one main difference here is that should your new array contain more entries than the actual array stored in the document to be modified, that second form using the "dot notation" to the indexed position is going to fail since it cannot "set" an index position which does not exist.
For this reason even though there are other pitfalls to "replacing" the array as the original examples show, it's a lot safer than attempting to update via the positional index in the stored document.
Note that this should be enough to have you at least started in the right direction. Making this work with multiple users possibly updating the data at once can become pretty complicated in terms of update statements for both checking and merging changes.
In most cases the simple "replace" will be more than adequate at least for a while. And of course the main lesson here should be to not loop "async" methods in places where it is completely unnecessary. Most of the time what you really want to "loop" is the construction of the statement, if of course any looping is required at all and most of the time it really isn't.
Addendum
Just in case you or anyone had it in mind to actually store an array of objects with the index
position values stored within them, this can become a little more complex, but it can also serve as an example of how to actually issue an update statement which does not "replace" the array and actually is safe considering it does not rely on indexed positions of the array but instead using matching conditions.
This is possible with the positional filtered $[<identifier>]
syntax introduced in MongoDB 3.6. This allows conditions to specify which element to update ( i.e by matching url ) instead of including the index positions within the statement directly. It's safer since if no matching element is found, then the syntax allows for not attempting to change anything at all.
Also as demonstration the method to $sort
the elements based on updated index
values is shown. Noting this actually uses the $push
modifier even though in this statement we are not actually adding anything to the array. Just reordering the elements. But it's how you actually do that atomically:
const { Schema, Types: { ObjectId } } = mongoose = require('mongoose');
const uri = 'mongodb://localhost:27017/longorder';
const opts = { useNewUrlParser: true };
// sensible defaults
mongoose.Promise = global.Promise;
mongoose.set('debug', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
// schema defs
const imageSchema = new Schema({
index: Number,
url: String
})
const userSchema = new Schema({
images: [imageSchema]
});
const User = mongoose.model('User', userSchema);
// log helper
const log = data => console.log(JSON.stringify(data, undefined, 2));
(async function() {
try {
const conn = await mongoose.connect(uri, opts);
// clean models
await Promise.all(
Object.entries(conn.models).map(([k,m]) => m.deleteMany())
);
// Create data
let _id = new ObjectId();
let user = await User.findOneAndUpdate(
{ _id },
{
'$push': {
'images': {
'$each': [
{ index: 2, url: '/one' },
{ index: 0, url: '/three' },
{ index: 1, url: '/two' }
],
'$sort': { 'index': 1 }
}
}
},
{ 'new': true, 'upsert': true }
);
log(user);
// Change order request
let orderImages = [
{ index: 2, url: '/three' },
{ index: 0, url: '/one' },
{ index: 1, url: '/two' }
];
let $set = { };
let arrayFilters = ;
for ( { index, url } of orderImages ) {
let key = url.replace(/^//,'');
arrayFilters.push({ [`${key}.url`]: url });
$set[`images.$[${key}].index`] = index;
}
let ops = [
// Update the index value of each matching item
{ 'updateOne': {
'filter': { _id },
'update': { $set },
arrayFilters
}},
// Re-sort the array by index value
{ 'updateOne': {
'filter': { _id },
'update': {
'$push': {
'images': { '$each': , '$sort': { 'index': 1 } }
}
}
}}
];
log(ops);
let response = await User.bulkWrite(ops);
log(response);
let newuser = await User.findOne({ _id });
log(newuser);
} catch(e) {
console.error(e)
} finally {
mongoose.disconnect()
}
})()
And the output, showing initial document state, the update and actual changes made:
Mongoose: users.deleteMany({}, {})
Mongoose: users.findOneAndUpdate({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { '$setOnInsert': { __v: 0 }, '$push': { images: { '$each': [ { _id: ObjectId("5bf6116621293f2ab3dec3d6"), index: 2, url: '/one' }, { _id: ObjectId("5bf6116621293f2ab3dec3d5"), index: 0, url: '/three' }, { _id: ObjectId("5bf6116621293f2ab3dec3d4"), index: 1, url: '/two' } ], '$sort': { index: 1 } } } }, { upsert: true, remove: false, projection: {}, returnOriginal: false })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 0,
"url": "/three"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 2,
"url": "/one"
}
]
}
[
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$set": {
"images.$[three].index": 2,
"images.$[one].index": 0,
"images.$[two].index": 1
}
},
"arrayFilters": [
{
"three.url": "/three"
},
{
"one.url": "/one"
},
{
"two.url": "/two"
}
]
}
},
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$push": {
"images": {
"$each": ,
"$sort": {
"index": 1
}
}
}
}
}
}
]
Mongoose: users.bulkWrite([ { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$set': { 'images.$[three].index': 2, 'images.$[one].index': 0, 'images.$[two].index': 1 } }, arrayFilters: [ { 'three.url': '/three' }, { 'one.url': '/one' }, { 'two.url': '/two' } ] } }, { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$push': { images: { '$each': , '$sort': { index: 1 } } } } } } ], {})
{
"ok": 1,
"writeErrors": ,
"writeConcernErrors": ,
"insertedIds": ,
"nInserted": 0,
"nUpserted": 0,
"nMatched": 2,
"nModified": 2,
"nRemoved": 0,
"upserted": ,
"lastOp": {
"ts": "6626503031506599940",
"t": 139
}
}
Mongoose: users.findOne({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { projection: {} })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 0,
"url": "/one"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 2,
"url": "/three"
}
]
}
So that is not actually the way you would do this. Basically there is no need to actually send an update request to the server for every single indexed position for the array. Also the update()
method is asynchronous, so it's not something you ever put inside a forEach()
which does not respect awaiting the completion of an asynchronous call.
Instead what is usually the most practical solution is to just $set
the entire array content in one request. Also mocking up your imagesOrder
to something practical since forEach()
even actually has the signature of .forEach((<element>,><index>) => ...
, which seems different to what you were expecting given the code in the question.
var imagesOrder = [
{ index: 0, url: '/one' }, { index: 1, url: '/two' }, { index: 2, url: '/three' }
];
let response = await Users.updateOne(
{ id },
{ "$set": { "images": imagesOrder.map(({ url }) => url) } }
);
// { "$set": { "images": ["/one","/two","/three"] } }
Much like the forEach()
a map()
does the same array iteration but with the difference that it actually returns an array generated by the processing function. This is actually what you want since all that is needed here is to simply extract the values of the url
property from each object.
Note the index
properties are actually already in order and really redundant here, but I'm just approximating what it sounds like you have from your question. Since an "array" actually maintains it's own order then such a property "should" be redundant and it would be advisable that your source array data actually conforms to this.
If however you managed to record such index
values in a way they are actually out of order, then the best solution is to add a sort()
:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
let response = await Users.updateOne(
{ id },
{ "$set": {
"images": imagesOrder.sort((a,b) => a.index - b.index)
.map(({ url }) => url)
}}
);
// { "$set": { "images": ["/one","/two","/three"] } }
As for what you "attempted", it's not really benefiting you in any way to actually attempt updating each element at a given position. But if you really wanted to see it done, then again you actually would just instead build up a single update request:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
var update = { $set: {} };
for ( let { url, index } of imagesOrder.sort((a,b) => a.index - b.index) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
Or in the case where the index
property was not there or irrelevant since the array is already ordered:
var imagesOrder = [
{ index: 2, url: '/three' }, { index: 0, url: '/one' }, { index: 1, url: '/two' }
];
for ( let [index, { url }] of Object.entries(imagesOrder) ) {
update.$set['images.'+index] = url;
}
/*
* Creates:
*
* { "$set": {
* "images.0": "/one",
* "images.1": "/two",
* "images.2": "/three"
* }}
*/
let response = await Users.updateOne({ id }, update);
So it's all pretty much the same thing. Note the common form of notation is actually a "string" for the key which includes the index position numerically. This is described in Dot Notation within the core documentation for the MongoDB query language.
The one main difference here is that should your new array contain more entries than the actual array stored in the document to be modified, that second form using the "dot notation" to the indexed position is going to fail since it cannot "set" an index position which does not exist.
For this reason even though there are other pitfalls to "replacing" the array as the original examples show, it's a lot safer than attempting to update via the positional index in the stored document.
Note that this should be enough to have you at least started in the right direction. Making this work with multiple users possibly updating the data at once can become pretty complicated in terms of update statements for both checking and merging changes.
In most cases the simple "replace" will be more than adequate at least for a while. And of course the main lesson here should be to not loop "async" methods in places where it is completely unnecessary. Most of the time what you really want to "loop" is the construction of the statement, if of course any looping is required at all and most of the time it really isn't.
Addendum
Just in case you or anyone had it in mind to actually store an array of objects with the index
position values stored within them, this can become a little more complex, but it can also serve as an example of how to actually issue an update statement which does not "replace" the array and actually is safe considering it does not rely on indexed positions of the array but instead using matching conditions.
This is possible with the positional filtered $[<identifier>]
syntax introduced in MongoDB 3.6. This allows conditions to specify which element to update ( i.e by matching url ) instead of including the index positions within the statement directly. It's safer since if no matching element is found, then the syntax allows for not attempting to change anything at all.
Also as demonstration the method to $sort
the elements based on updated index
values is shown. Noting this actually uses the $push
modifier even though in this statement we are not actually adding anything to the array. Just reordering the elements. But it's how you actually do that atomically:
const { Schema, Types: { ObjectId } } = mongoose = require('mongoose');
const uri = 'mongodb://localhost:27017/longorder';
const opts = { useNewUrlParser: true };
// sensible defaults
mongoose.Promise = global.Promise;
mongoose.set('debug', true);
mongoose.set('useFindAndModify', false);
mongoose.set('useCreateIndex', true);
// schema defs
const imageSchema = new Schema({
index: Number,
url: String
})
const userSchema = new Schema({
images: [imageSchema]
});
const User = mongoose.model('User', userSchema);
// log helper
const log = data => console.log(JSON.stringify(data, undefined, 2));
(async function() {
try {
const conn = await mongoose.connect(uri, opts);
// clean models
await Promise.all(
Object.entries(conn.models).map(([k,m]) => m.deleteMany())
);
// Create data
let _id = new ObjectId();
let user = await User.findOneAndUpdate(
{ _id },
{
'$push': {
'images': {
'$each': [
{ index: 2, url: '/one' },
{ index: 0, url: '/three' },
{ index: 1, url: '/two' }
],
'$sort': { 'index': 1 }
}
}
},
{ 'new': true, 'upsert': true }
);
log(user);
// Change order request
let orderImages = [
{ index: 2, url: '/three' },
{ index: 0, url: '/one' },
{ index: 1, url: '/two' }
];
let $set = { };
let arrayFilters = ;
for ( { index, url } of orderImages ) {
let key = url.replace(/^//,'');
arrayFilters.push({ [`${key}.url`]: url });
$set[`images.$[${key}].index`] = index;
}
let ops = [
// Update the index value of each matching item
{ 'updateOne': {
'filter': { _id },
'update': { $set },
arrayFilters
}},
// Re-sort the array by index value
{ 'updateOne': {
'filter': { _id },
'update': {
'$push': {
'images': { '$each': , '$sort': { 'index': 1 } }
}
}
}}
];
log(ops);
let response = await User.bulkWrite(ops);
log(response);
let newuser = await User.findOne({ _id });
log(newuser);
} catch(e) {
console.error(e)
} finally {
mongoose.disconnect()
}
})()
And the output, showing initial document state, the update and actual changes made:
Mongoose: users.deleteMany({}, {})
Mongoose: users.findOneAndUpdate({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { '$setOnInsert': { __v: 0 }, '$push': { images: { '$each': [ { _id: ObjectId("5bf6116621293f2ab3dec3d6"), index: 2, url: '/one' }, { _id: ObjectId("5bf6116621293f2ab3dec3d5"), index: 0, url: '/three' }, { _id: ObjectId("5bf6116621293f2ab3dec3d4"), index: 1, url: '/two' } ], '$sort': { index: 1 } } } }, { upsert: true, remove: false, projection: {}, returnOriginal: false })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 0,
"url": "/three"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 2,
"url": "/one"
}
]
}
[
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$set": {
"images.$[three].index": 2,
"images.$[one].index": 0,
"images.$[two].index": 1
}
},
"arrayFilters": [
{
"three.url": "/three"
},
{
"one.url": "/one"
},
{
"two.url": "/two"
}
]
}
},
{
"updateOne": {
"filter": {
"_id": "5bf6116621293f2ab3dec3d3"
},
"update": {
"$push": {
"images": {
"$each": ,
"$sort": {
"index": 1
}
}
}
}
}
}
]
Mongoose: users.bulkWrite([ { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$set': { 'images.$[three].index': 2, 'images.$[one].index': 0, 'images.$[two].index': 1 } }, arrayFilters: [ { 'three.url': '/three' }, { 'one.url': '/one' }, { 'two.url': '/two' } ] } }, { updateOne: { filter: { _id: 5bf6116621293f2ab3dec3d3 }, update: { '$push': { images: { '$each': , '$sort': { index: 1 } } } } } } ], {})
{
"ok": 1,
"writeErrors": ,
"writeConcernErrors": ,
"insertedIds": ,
"nInserted": 0,
"nUpserted": 0,
"nMatched": 2,
"nModified": 2,
"nRemoved": 0,
"upserted": ,
"lastOp": {
"ts": "6626503031506599940",
"t": 139
}
}
Mongoose: users.findOne({ _id: ObjectId("5bf6116621293f2ab3dec3d3") }, { projection: {} })
{
"_id": "5bf6116621293f2ab3dec3d3",
"__v": 0,
"images": [
{
"_id": "5bf6116621293f2ab3dec3d6",
"index": 0,
"url": "/one"
},
{
"_id": "5bf6116621293f2ab3dec3d4",
"index": 1,
"url": "/two"
},
{
"_id": "5bf6116621293f2ab3dec3d5",
"index": 2,
"url": "/three"
}
]
}
edited Nov 22 at 2:17
answered Nov 22 at 1:21
Neil Lunn
96.3k22169179
96.3k22169179
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
add a comment |
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
Thank you for this great explanation. This is super helpful!
– Kris
Nov 26 at 16:57
add a comment |
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