Trying to write a recursive asynchronous search in JavaScript - javascript

I am trying to write some code that searches through a bunch of objects in a MongoDB database. I want to pull the objects from the database by ID, then those objects have ID references. The program should be searching for a specific ID through this process, first getting object from id, then ids from the object.
async function objectFinder(ID1, ID2, depth, previousList = []) {
let route = []
if (ID1 == ID2) {
return [ID2]
} else {
previousList.push(ID1)
let obj1 = await findObjectByID(ID1)
let connectedID = obj1.connections.concat(obj1.inclusions) //creates array of both references to object and references from object
let mapPromises = connectedID.map(async (id) => {
return findID(id) //async function
})
let fulfilled = await Promise.allSettled(mapPromises)
let list = fulfilled.map((object) => {
return object.value.main, object.value.included
})
list = list.filter(id => !previousList.includes(id))
for (id of list) {
await objectFinder(id, ID2, depth - 1, previousList).then(result => {
route = [ID1].concat(result)
if (route[route.length - 1] == ID2) {
return route
}})
}
}
if (route[route.length - 1] == ID2) {
return route
}
}
I am not sure how to make it so that my code works like a tree search, with each object and ID being a node.

I didn't look too much into your code as I strongly believe in letting your database do the work for you if possible.
In this case Mongo has the $graphLookup aggregation stage, which allows recursive lookups. here is a quick example on how to use it:
db.collection.aggregate([
{
$match: {
_id: 1,
}
},
{
"$graphLookup": {
"from": "collection",
"startWith": "$inclusions",
"connectFromField": "inclusions",
"connectToField": "_id",
"as": "matches",
}
},
{
//the rest of the pipeline is just to restore the original structure you don't need this
$addFields: {
matches: {
"$concatArrays": [
[
{
_id: "$_id",
inclusions: "$inclusions"
}
],
"$matches"
]
}
}
},
{
$unwind: "$matches"
},
{
"$replaceRoot": {
"newRoot": "$matches"
}
}
])
Mongo Playground
If for whatever reason you want to keep this in code then I would take a look at your for loop:
for (id of list) {
await objectFinder(id, ID2, depth - 1, previousList).then(result => {
route = [ID1].concat(result);
if (route[route.length - 1] == ID2) {
return route;
}
});
}
Just from a quick glance I can tell you're executing this:
route = [ID1].concat(result);
Many times at the same level. Additional I could not understand your bottom return statements, I feel like there might be an issue there.

Related

Nesting multiple [Op.not] queries in a single where clause

I've got a filter that allows users to indicate themes and genres they would like removed from the search results. This is an OR, not AND situation, so if either a theme or a genre is matched, it should be removed from the pool.
If I run the query below with a single [Op.not] clause, the themes and genres filter correctly. When I attempt to combine them as show in the example, only the genres [Op.not] executes. I assume I've chained them incorrectly in the where clause?
Code Example
//Variables to store filters from JSON body
let sortBy = [req.body.galleryFilters.sortBy, 'ASC']
let hiddenThemes = [];
let hiddenGenres = [];
//Parse the body for activeFilters create and array of Active Filters
req.body.galleryFilters.themes.forEach(theme => {
if(theme.hidden === true) {
hiddenThemes.push(theme.name)
}
})
req.body.galleryFilters.genres.forEach(genre => {
if(genre.hidden === true) {
hiddenGenres.push(genre.name)
}
})
//use variables above to create new playlist obje
const playlists = await db.playlists.findAll({
where: {
[Op.not]: {
themes: {
[Op.overlap]: hiddenThemes
},
},
[Op.not]: {
genres: {
[Op.overlap]: hiddenGenres
},
},
},
order: [[req.body.galleryFilters.sortBy, 'ASC']]
});
return res.send(playlists);
}
});
I'm too inexperienced to give a thorough explanation but the revision below seems to work for now:
const playlists = await db.playlists.findAll({
where: {
[Op.not]: {
[Op.or]: {
themes: { [Op.overlap]: hiddenThemes },
genres: { [Op.overlap]: hiddenGenres },
}
}
},
order: [[req.body.galleryFilters.sortBy, 'ASC']]
});
return res.send(playlists);
}

How can I loop through a non determined JSON key and send a message with it?

So, I made a command which registers pokémon you are shiny hunting for, how many you have got, and how many eggs it took/is taking for you to get the shiny, and it works fine. My problem is that some people forget the pokémon they did register in that storage, and so I would like to be able to send a message containing all the pokémon they registered in the Storage, like this:
You have registered the following pokémon:
(All the pokémon you registered)
But, I don't know how to loop through the keys that are inside of the user's ID. Here's how my json file looks:
{
"User's ID": {
"Pokémon": {
"encounters": value,
"shinies": value
},
"Pokémon": {
"encounters": value,
"shinies": value
}
}
}
I have tried looping like this:
const path = require('path');
const fs = require('fs');
const shiniesDataPath = path.resolve(__dirname, './Storage/shiniesData.json');
function loadShiniesData() {
return JSON.parse(fs.readFileSync(shiniesDataPath).toString());
}
const shiniesData = loadShiniesData();
var trainer = shiniesData[message.author.id];
if (args[0] === 'all') {
for (var trainer in shiniesData) {
message.channel.send([trainer])
}
return;
}
But it only loops through the ID's.
i think the example code that you have provided is not entirely clear.
like what do you have var trainer in two places.
var trainer = shiniesData[message.author.id];
if (args[0] === 'all') {
for (var trainer in shiniesData) {
message.channel.send([trainer])
}
return;
}
I am guessing this what you are looking for
if (args[0] === 'all') {
Object.keys(shiniesData).forEach(userId => {
const monsterNames = Object.keys(shiniesData[userId]);
message.channel.send(userId, monsterNames]);
});
return;
}
A JSON object should not have multiple identical keys, rather what you can do is assign the Pokémon key to an array, like this:
{
"User's ID": {
"Pokémon": [
{
"encounters": value,
"shinies": value
},
{
"encounters": value,
"shinies": value
}
]
}
}
In order to access the keys, let's say the object above was assigned to variable obj. In order to access the keys in an object, you can do
Object.keys(obj).forEach((key) => {
// Do something
})
However if you switch to an array as I have done, I'd imagine you would want to do something like this instead:
obj['Pokémon'].forEach((item) => {
// Do something
})
where obj['Pokémon'] returns the array mapped to the key 'Pokémon', and .foreach iterates through each item in the array, and you can access it within the anonymous function (surrounded by curly braces) via the variable item.
const message = {
author: {
id: "1234"
},
channel: {
send: console.log
}
}
// stubbed function
function loadShiniesData() {
return {
"1234": {
"Pikachu": {
"encounters": 2,
"shinies": 3
},
"Fenekin": {
"encounters": 5,
"shinies": 1
}
}
}
}
const shiniesData = loadShiniesData();
const trainer = shiniesData[message.author.id];
message.channel.send('You have registered the following pokemon:\n' + Object.keys(trainer).join(", "));
Once you've retrieved the users data then you can use Object.keys to get an array of the pokemon names.

Apollo GraphQL updateQuery to typePolicy

I am beating my head against a wall. I have updated to Apollo 3, and cannot figure out how to migrate an updateQuery to a typePolicy. I am doing basic continuation based pagination, and this is how I used to merged the results of fetchMore:
await fetchMore({
query: MessagesByThreadIDQuery,
variables: {
threadId: threadId,
limit: Configuration.MessagePageSize,
continuation: token
},
updateQuery: (prev, curr) => {
// Extract our updated message page.
const last = prev.messagesByThreadId.messages ?? []
const next = curr.fetchMoreResult?.messagesByThreadId.messages ?? []
return {
messagesByThreadId: {
__typename: 'MessagesContinuation',
messages: [...last, ...next],
continuation: curr.fetchMoreResult?.messagesByThreadId.continuation
}
}
}
I have made an attempt to write the merge typePolicy myself, but it just continually loads and throws errors about duplicate identifiers in the Apollo cache. Here is what my typePolicy looks like for my query.
typePolicies: {
Query: {
fields: {
messagesByThreadId: {
keyArgs: false,
merge: (existing, incoming, args): IMessagesContinuation => {
const typedExisting: IMessagesContinuation | undefined = existing
const typedIncoming: IMessagesContinuation | undefined = incoming
const existingMessages = (typedExisting?.messages ?? [])
const incomingMessages = (typedIncoming?.messages ?? [])
const result = existing ? {
__typename: 'MessageContinuation',
messages: [...existingMessages, ...incomingMessages],
continuation: typedIncoming?.continuation
} : incoming
return result
}
}
}
}
}
So I was able to solve my use-case. It seems way harder than it really needs to be. I essentially have to attempt to locate existing items matching the incoming and overwrite them, as well as add any new items that don't yet exist in the cache.
I also have to only apply this logic if a continuation token was provided, because if it's null or undefined, I should just use the incoming value because that indicates that we are doing an initial load.
My document is shaped like this:
{
"items": [{ id: string, ...others }],
"continuation": "some_token_value"
}
I created a generic type policy that I can use for all my documents that have a similar shape. It allows me to specify the name of the items property, what the key args are that I want to cache on, and the name of the graphql type.
export function ContinuationPolicy(keyArgs: Array<string>, itemPropertyKey: string, typeName: string) {
return {
keyArgs,
merge(existing: any, incoming: any, args: any) {
if (!!existing && !!args.args?.continuation) {
const existingItems = (existing ? existing[itemPropertyKey] : [])
const incomingItems = (incoming ? incoming[itemPropertyKey] : [])
let items: Array<any> = [...existingItems]
for (let i = 0; i < incomingItems.length; i++) {
const current = incomingItems[i] as any
const found = items.findIndex(m => m.__ref === current.__ref)
if (found > -1) {
items[found] === current
} else {
items = [...items, current]
}
}
// This new data is a continuation of the last data.
return {
__typename: typeName,
[itemPropertyKey]: items,
continuation: incoming.continuation
}
} else {
// When we have no existing data in the cache, we'll just use the incoming data.
return incoming
}
}
}
}

Getting a list of unique fields within a collection including nested [duplicate]

I'd like to get the names of all the keys in a MongoDB collection.
For example, from this:
db.things.insert( { type : ['dog', 'cat'] } );
db.things.insert( { egg : ['cat'] } );
db.things.insert( { type : [] } );
db.things.insert( { hello : [] } );
I'd like to get the unique keys:
type, egg, hello
You could do this with MapReduce:
mr = db.runCommand({
"mapreduce" : "my_collection",
"map" : function() {
for (var key in this) { emit(key, null); }
},
"reduce" : function(key, stuff) { return null; },
"out": "my_collection" + "_keys"
})
Then run distinct on the resulting collection so as to find all the keys:
db[mr.result].distinct("_id")
["foo", "bar", "baz", "_id", ...]
With Kristina's answer as inspiration, I created an open source tool called Variety which does exactly this: https://github.com/variety/variety
You can use aggregation with the new $objectToArray aggregation operator in version 3.4.4 to convert all top key-value pairs into document arrays, followed by $unwind and $group with $addToSet to get distinct keys across the entire collection. (Use $$ROOT for referencing the top level document.)
db.things.aggregate([
{"$project":{"arrayofkeyvalue":{"$objectToArray":"$$ROOT"}}},
{"$unwind":"$arrayofkeyvalue"},
{"$group":{"_id":null,"allkeys":{"$addToSet":"$arrayofkeyvalue.k"}}}
])
You can use the following query for getting keys in a single document.
db.things.aggregate([
{"$match":{_id: "<<ID>>"}}, /* Replace with the document's ID */
{"$project":{"arrayofkeyvalue":{"$objectToArray":"$$ROOT"}}},
{"$project":{"keys":"$arrayofkeyvalue.k"}}
])
A cleaned up and reusable solution using pymongo:
from pymongo import MongoClient
from bson import Code
def get_keys(db, collection):
client = MongoClient()
db = client[db]
map = Code("function() { for (var key in this) { emit(key, null); } }")
reduce = Code("function(key, stuff) { return null; }")
result = db[collection].map_reduce(map, reduce, "myresults")
return result.distinct('_id')
Usage:
get_keys('dbname', 'collection')
>> ['key1', 'key2', ... ]
If your target collection is not too large, you can try this under mongo shell client:
var allKeys = {};
db.YOURCOLLECTION.find().forEach(function(doc){Object.keys(doc).forEach(function(key){allKeys[key]=1})});
allKeys;
If you are using mongodb 3.4.4 and above then you can use below aggregation using $objectToArray and $group aggregation
db.collection.aggregate([
{ "$project": {
"data": { "$objectToArray": "$$ROOT" }
}},
{ "$project": { "data": "$data.k" }},
{ "$unwind": "$data" },
{ "$group": {
"_id": null,
"keys": { "$addToSet": "$data" }
}}
])
Here is the working example
Try this:
doc=db.thinks.findOne();
for (key in doc) print(key);
Using python. Returns the set of all top-level keys in the collection:
#Using pymongo and connection named 'db'
reduce(
lambda all_keys, rec_keys: all_keys | set(rec_keys),
map(lambda d: d.keys(), db.things.find()),
set()
)
Here is the sample worked in Python:
This sample returns the results inline.
from pymongo import MongoClient
from bson.code import Code
mapper = Code("""
function() {
for (var key in this) { emit(key, null); }
}
""")
reducer = Code("""
function(key, stuff) { return null; }
""")
distinctThingFields = db.things.map_reduce(mapper, reducer
, out = {'inline' : 1}
, full_response = True)
## do something with distinctThingFields['results']
I am surprise, no one here has ans by using simple javascript and Set logic to automatically filter the duplicates values, simple example on mongo shellas below:
var allKeys = new Set()
db.collectionName.find().forEach( function (o) {for (key in o ) allKeys.add(key)})
for(let key of allKeys) print(key)
This will print all possible unique keys in the collection name: collectionName.
I think the best way do this as mentioned here is in mongod 3.4.4+ but without using the $unwind operator and using only two stages in the pipeline. Instead we can use the $mergeObjects and $objectToArray operators.
In the $group stage, we use the $mergeObjects operator to return a single document where key/value are from all documents in the collection.
Then comes the $project where we use $map and $objectToArray to return the keys.
let allTopLevelKeys = [
{
"$group": {
"_id": null,
"array": {
"$mergeObjects": "$$ROOT"
}
}
},
{
"$project": {
"keys": {
"$map": {
"input": { "$objectToArray": "$array" },
"in": "$$this.k"
}
}
}
}
];
Now if we have a nested documents and want to get the keys as well, this is doable. For simplicity, let consider a document with simple embedded document that look like this:
{field1: {field2: "abc"}, field3: "def"}
{field1: {field3: "abc"}, field4: "def"}
The following pipeline yield all keys (field1, field2, field3, field4).
let allFistSecondLevelKeys = [
{
"$group": {
"_id": null,
"array": {
"$mergeObjects": "$$ROOT"
}
}
},
{
"$project": {
"keys": {
"$setUnion": [
{
"$map": {
"input": {
"$reduce": {
"input": {
"$map": {
"input": {
"$objectToArray": "$array"
},
"in": {
"$cond": [
{
"$eq": [
{
"$type": "$$this.v"
},
"object"
]
},
{
"$objectToArray": "$$this.v"
},
[
"$$this"
]
]
}
}
},
"initialValue": [
],
"in": {
"$concatArrays": [
"$$this",
"$$value"
]
}
}
},
"in": "$$this.k"
}
}
]
}
}
}
]
With a little effort, we can get the key for all subdocument in an array field where the elements are object as well.
This works fine for me:
var arrayOfFieldNames = [];
var items = db.NAMECOLLECTION.find();
while(items.hasNext()) {
var item = items.next();
for(var index in item) {
arrayOfFieldNames[index] = index;
}
}
for (var index in arrayOfFieldNames) {
print(index);
}
Maybe slightly off-topic, but you can recursively pretty-print all keys/fields of an object:
function _printFields(item, level) {
if ((typeof item) != "object") {
return
}
for (var index in item) {
print(" ".repeat(level * 4) + index)
if ((typeof item[index]) == "object") {
_printFields(item[index], level + 1)
}
}
}
function printFields(item) {
_printFields(item, 0)
}
Useful when all objects in a collection has the same structure.
To get a list of all the keys minus _id, consider running the following aggregate pipeline:
var keys = db.collection.aggregate([
{ "$project": {
"hashmaps": { "$objectToArray": "$$ROOT" }
} },
{ "$group": {
"_id": null,
"fields": { "$addToSet": "$hashmaps.k" }
} },
{ "$project": {
"keys": {
"$setDifference": [
{
"$reduce": {
"input": "$fields",
"initialValue": [],
"in": { "$setUnion" : ["$$value", "$$this"] }
}
},
["_id"]
]
}
}
}
]).toArray()[0]["keys"];
I know I am late to the party, but if you want a quick solution in python finding all keys (even the nested ones) you could do with a recursive function:
def get_keys(dl, keys=None):
keys = keys or []
if isinstance(dl, dict):
keys += dl.keys()
list(map(lambda x: get_keys(x, keys), dl.values()))
elif isinstance(dl, list):
list(map(lambda x: get_keys(x, keys), dl))
return list(set(keys))
and use it like:
dl = db.things.find_one({})
get_keys(dl)
if your documents do not have identical keys you can do:
dl = db.things.find({})
list(set(list(map(get_keys, dl))[0]))
but this solution can for sure be optimized.
Generally this solution is basically solving finding keys in nested dicts, so this is not mongodb specific.
Based on #Wolkenarchitekt answer: https://stackoverflow.com/a/48117846/8808983, I write a script that can find patterns in all keys in the db and I think it can help others reading this thread:
"""
Python 3
This script get list of patterns and print the collections that contains fields with this patterns.
"""
import argparse
import pymongo
from bson import Code
# initialize mongo connection:
def get_db():
client = pymongo.MongoClient("172.17.0.2")
db = client["Data"]
return db
def get_commandline_options():
description = "To run use: python db_fields_pattern_finder.py -p <list_of_patterns>"
parser = argparse.ArgumentParser(description=description)
parser.add_argument('-p', '--patterns', nargs="+", help='List of patterns to look for in the db.', required=True)
return parser.parse_args()
def report_matching_fields(relevant_fields_by_collection):
print("Matches:")
for collection_name in relevant_fields_by_collection:
if relevant_fields_by_collection[collection_name]:
print(f"{collection_name}: {relevant_fields_by_collection[collection_name]}")
# pprint(relevant_fields_by_collection)
def get_collections_names(db):
"""
:param pymongo.database.Database db:
:return list: collections names
"""
return db.list_collection_names()
def get_keys(db, collection):
"""
See: https://stackoverflow.com/a/48117846/8808983
:param db:
:param collection:
:return:
"""
map = Code("function() { for (var key in this) { emit(key, null); } }")
reduce = Code("function(key, stuff) { return null; }")
result = db[collection].map_reduce(map, reduce, "myresults")
return result.distinct('_id')
def get_fields(db, collection_names):
fields_by_collections = {}
for collection_name in collection_names:
fields_by_collections[collection_name] = get_keys(db, collection_name)
return fields_by_collections
def get_matches_fields(fields_by_collections, patterns):
relevant_fields_by_collection = {}
for collection_name in fields_by_collections:
relevant_fields = [field for field in fields_by_collections[collection_name] if
[pattern for pattern in patterns if
pattern in field]]
relevant_fields_by_collection[collection_name] = relevant_fields
return relevant_fields_by_collection
def main(patterns):
"""
:param list patterns: List of strings to look for in the db.
"""
db = get_db()
collection_names = get_collections_names(db)
fields_by_collections = get_fields(db, collection_names)
relevant_fields_by_collection = get_matches_fields(fields_by_collections, patterns)
report_matching_fields(relevant_fields_by_collection)
if __name__ == '__main__':
args = get_commandline_options()
main(args.patterns)
As per the mongoldb documentation, a combination of distinct
Finds the distinct values for a specified field across a single collection or view and returns the results in an array.
and indexes collection operations are what would return all possible values for a given key, or index:
Returns an array that holds a list of documents that identify and describe the existing indexes on the collection
So in a given method one could do use a method like the following one, in order to query a collection for all it's registered indexes, and return, say an object with the indexes for keys (this example uses async/await for NodeJS, but obviously you could use any other asynchronous approach):
async function GetFor(collection, index) {
let currentIndexes;
let indexNames = [];
let final = {};
let vals = [];
try {
currentIndexes = await collection.indexes();
await ParseIndexes();
//Check if a specific index was queried, otherwise, iterate for all existing indexes
if (index && typeof index === "string") return await ParseFor(index, indexNames);
await ParseDoc(indexNames);
await Promise.all(vals);
return final;
} catch (e) {
throw e;
}
function ParseIndexes() {
return new Promise(function (result) {
let err;
for (let ind in currentIndexes) {
let index = currentIndexes[ind];
if (!index) {
err = "No Key For Index "+index; break;
}
let Name = Object.keys(index.key);
if (Name.length === 0) {
err = "No Name For Index"; break;
}
indexNames.push(Name[0]);
}
return result(err ? Promise.reject(err) : Promise.resolve());
})
}
async function ParseFor(index, inDoc) {
if (inDoc.indexOf(index) === -1) throw "No Such Index In Collection";
try {
await DistinctFor(index);
return final;
} catch (e) {
throw e
}
}
function ParseDoc(doc) {
return new Promise(function (result) {
let err;
for (let index in doc) {
let key = doc[index];
if (!key) {
err = "No Key For Index "+index; break;
}
vals.push(new Promise(function (pushed) {
DistinctFor(key)
.then(pushed)
.catch(function (err) {
return pushed(Promise.resolve());
})
}))
}
return result(err ? Promise.reject(err) : Promise.resolve());
})
}
async function DistinctFor(key) {
if (!key) throw "Key Is Undefined";
try {
final[key] = await collection.distinct(key);
} catch (e) {
final[key] = 'failed';
throw e;
}
}
}
So querying a collection with the basic _id index, would return the following (test collection only has one document at the time of the test):
Mongo.MongoClient.connect(url, function (err, client) {
assert.equal(null, err);
let collection = client.db('my db').collection('the targeted collection');
GetFor(collection, '_id')
.then(function () {
//returns
// { _id: [ 5ae901e77e322342de1fb701 ] }
})
.catch(function (err) {
//manage your error..
})
});
Mind you, this uses methods native to the NodeJS Driver. As some other answers have suggested, there are other approaches, such as the aggregate framework. I personally find this approach more flexible, as you can easily create and fine-tune how to return the results. Obviously, this only addresses top-level attributes, not nested ones.
Also, to guarantee that all documents are represented should there be secondary indexes (other than the main _id one), those indexes should be set as required.
We can achieve this by Using mongo js file. Add below code in your getCollectionName.js file and run js file in the console of Linux as given below :
mongo --host 192.168.1.135 getCollectionName.js
db_set = connect("192.168.1.135:27017/database_set_name"); // for Local testing
// db_set.auth("username_of_db", "password_of_db"); // if required
db_set.getMongo().setSlaveOk();
var collectionArray = db_set.getCollectionNames();
collectionArray.forEach(function(collectionName){
if ( collectionName == 'system.indexes' || collectionName == 'system.profile' || collectionName == 'system.users' ) {
return;
}
print("\nCollection Name = "+collectionName);
print("All Fields :\n");
var arrayOfFieldNames = [];
var items = db_set[collectionName].find();
// var items = db_set[collectionName].find().sort({'_id':-1}).limit(100); // if you want fast & scan only last 100 records of each collection
while(items.hasNext()) {
var item = items.next();
for(var index in item) {
arrayOfFieldNames[index] = index;
}
}
for (var index in arrayOfFieldNames) {
print(index);
}
});
quit();
Thanks #ackuser
Following the thread from #James Cropcho's answer, I landed on the following which I found to be super easy to use. It is a binary tool, which is exactly what I was looking for:
mongoeye.
Using this tool it took about 2 minutes to get my schema exported from command line.
I know this question is 10 years old but there is no C# solution and this took me hours to figure out. I'm using the .NET driver and System.Linq to return a list of the keys.
var map = new BsonJavaScript("function() { for (var key in this) { emit(key, null); } }");
var reduce = new BsonJavaScript("function(key, stuff) { return null; }");
var options = new MapReduceOptions<BsonDocument, BsonDocument>();
var result = await collection.MapReduceAsync(map, reduce, options);
var list = result.ToEnumerable().Select(item => item["_id"].ToString());
This one lines extracts all keys from a collection into a comma separated sorted string:
db.<collection>.find().map((x) => Object.keys(x)).reduce((a, e) => {for (el of e) { if(!a.includes(el)) { a.push(el) } }; return a}, []).sort((a, b) => a.toLowerCase() > b.toLowerCase()).join(", ")
The result of this query typically looks like this:
_class, _id, address, city, companyName, country, emailId, firstName, isAssigned, isLoggedIn, lastLoggedIn, lastName, location, mobile, printName, roleName, route, state, status, token
I extended Carlos LM's solution a bit so it's more detailed.
Example of a schema:
var schema = {
_id: 123,
id: 12,
t: 'title',
p: 4.5,
ls: [{
l: 'lemma',
p: {
pp: 8.9
}
},
{
l: 'lemma2',
p: {
pp: 8.3
}
}
]
};
Type into the console:
var schemafy = function(schema, i, limit) {
var i = (typeof i !== 'undefined') ? i : 1;
var limit = (typeof limit !== 'undefined') ? limit : false;
var type = '';
var array = false;
for (key in schema) {
type = typeof schema[key];
array = (schema[key] instanceof Array) ? true : false;
if (type === 'object') {
print(Array(i).join(' ') + key+' <'+((array) ? 'array' : type)+'>:');
schemafy(schema[key], i+1, array);
} else {
print(Array(i).join(' ') + key+' <'+type+'>');
}
if (limit) {
break;
}
}
}
Run:
schemafy(db.collection.findOne());
Output
_id <number>
id <number>
t <string>
p <number>
ls <object>:
0 <object>:
l <string>
p <object>:
pp <number>
I was trying to write in nodejs and finally came up with this:
db.collection('collectionName').mapReduce(
function() {
for (var key in this) {
emit(key, null);
}
},
function(key, stuff) {
return null;
}, {
"out": "allFieldNames"
},
function(err, results) {
var fields = db.collection('allFieldNames').distinct('_id');
fields
.then(function(data) {
var finalData = {
"status": "success",
"fields": data
};
res.send(finalData);
delteCollection(db, 'allFieldNames');
})
.catch(function(err) {
res.send(err);
delteCollection(db, 'allFieldNames');
});
});
After reading the newly created collection "allFieldNames", delete it.
db.collection("allFieldNames").remove({}, function (err,result) {
db.close();
return;
});
I have 1 simpler work around...
What you can do is while inserting data/document into your main collection "things" you must insert the attributes in 1 separate collection lets say "things_attributes".
so every time you insert in "things", you do get from "things_attributes" compare values of that document with your new document keys if any new key present append it in that document and again re-insert it.
So things_attributes will have only 1 document of unique keys which you can easily get when ever you require by using findOne()

Match two values in a collection

I have two values I need to match as you can see in the picture below:
I tried something like this:
const index = state.locks.users.findIndex(
stateUser => stateUser._id === action.payload.customerPayload.accessid
But I’m getting the error:
findIndex of undefined.
And I guess that’s because of locks being an array.
But I’m really uncertain how to fix this issue. Should I have multiple findIndexes? One for the lock and one for to match the users?
Thanks for reading my post. And I appreciate all the help I can get.
The code snippet should be
let itemIndex = -1;
state.locks.map((lock) => {
lock.users.findIndex(...)
});
Assuming state is an object containing locks array.
My suggestion to you is do a double for loop (as you've already figured) to get the user object that you need.
Consider the following snippet (adjust to your data structure):
let state = {
locks: [
{
users: [
{ _id: '123' },
{ _id: '456' }
]
},
{
users: [
{ _id: '678' },
{ _id: '789' }
]
},
]
};
function getUserObjByID(stateObj, userID) {
for (let usersObject of state.locks) {
for (let user of usersObject.users) {
if (user._id === userID) {
return user;
}
}
}
}
let myObj = getUserObjByID(state, '678');
console.log(myObj);
So it works now. What I had to do with my reducer was this:
case 'REMOVE_USER':
return {
...state,
locks: state.locks.map(lock => {
return {
...lock,
users: lock.users
? lock.users.filter(
user => user._id != action.payload.customerPayload.accessid
)
: []
}
})
}

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