CODEWITHSUNDEEP
javascriptnode.jsmongodbmongoose
David
David

Reputation: 341

How can I return only the string value of an object from a MongoDB array

valueOf() returns this:

[
   {},
   { toUser: '5ed9d49c7e516616600eb693' },       
   { toUser: '5ed9d49c7e516616600eb693' },       
   { toUser: '5ed9d49c7e516616600eb693' },       
   { toUser: '5ed9d3897e516616600eb692' }        
]

I want to return only the value like "5ed9d3897e516616600eb692" or whatever toUser has. How?

Upvotes: 1

Views: 1342

Answers (3)

Tom Slabbaert
Tom Slabbaert

Reputation: 22276

This can be done in a couple of different ways, the best of which is using distinct:

db.collection.distinct("toUser")

Output will be:

[
    '5ed9d49c7e516616600eb693',
    '5ed9d49c7e516616600eb693',
    '5ed9d49c7e516616600eb693',
    '5ed9d3897e516616600eb692'
]

Upvotes: 2

shiva
shiva

Reputation: 27

You can use following query to convert object to string

> db.objectidToStringDemo.aggregate([{$project: {toUser: {$toString: "$toUser"}}}]);

Upvotes: 0

brk
brk

Reputation: 50291

You can use reduce and inside callback check if the object has any key using Object.keys and length. If it has k then push the value using Object.values into the accumulator array

let data = [{},
  {
    toUser: '5ed9d49c7e516616600eb693'
  },
  {
    toUser: '5ed9d49c7e516616600eb693'
  },
  {
    toUser: '5ed9d49c7e516616600eb693'
  },
  {
    toUser: '5ed9d3897e516616600eb692'
  }
];
let filterdValue = data.reduce((acc, curr) => {
  const objKey = Object.keys(curr);
  if (objKey.length > 0) {
    acc.push(...Object.values(curr))
  }
  return acc;
}, []);
console.log(filterdValue)

Upvotes: 1

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