How do I turn key value pairs in object into array of objects?

Question

I have some code that outputs an object with key value pairs. Like so:

{"a" : "1", "b" : "2", "c" : "3"}

I would like to change that output to this instead:

[{"a" : "1"}, {"b" : "2"}, {"c" : "3"}]

I have fiddled around with Object.entries(), Object.assign() and Array.map() without getting much further. I have put so much time into this now so I figured it was time to ask for some help.

The initial data is from req.query which I have then managed to convert from:

{a: "1", b: "2", c: "3"}

into

{"x.a": "1", "x.b": "2", "x.c": "3"}

This will eventually become a mongoDB query.

Below is what I have so far.

let obj = Object.entries(req.query);
obj = obj.map(([key, val]) => ["x."+ key, val]);
let newobj = Object.assign(...obj.map(([k, v]) => ({ [k]: v })));

which gives:

{"x.a": "1", "x.b": "2", "x.c": "3"}

so, as per my initial question. How do I turn this into:

[{"x.a" : "1"}, {"x.b" : "2"}, {"x.c" : "3"}]

i know this code is not pretty and there is likely a number of ways to shorten this down... — 75martin
– 75martin, Commented Sep 2, 2019 at 11:18

Code Maniac · Accepted Answer · 2019-09-02 11:18:22Z

2

You can use Object.entries and map

let obj = {
  "a": "1",
  "b": "2",
  "c": "3"
}

let final = Object.entries(obj).map(([k, v]) => ({
  [`x.${k}`]: v
}))

console.log(final)

If you just want key instead of x.a, you can use simply use

 [k] : v

edited Sep 2, 2019 at 11:18

answered Sep 2, 2019 at 11:13

Code Maniac

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6 Comments

mplungjan Over a year ago

No dupe available at all?

Code Maniac Over a year ago

@mplungjan sorry not so good at finding them, if you found something you have my vote also there

mplungjan Over a year ago

Add mongo and they will even be closer

Code Maniac Over a year ago

@mplungjan okay thanks :) what this line means Add mongo and they will even be closer ?

mplungjan Over a year ago

This will eventually become a mongoDB query. so I added mongo to the search and found more conversions from array to mongoDB arrays

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