lodash: mapping array to object

Question

Is there a built-in lodash function to take this:

var params = [
    { name: \'foo\', input: \'bar\' },
    { name: \'baz\', input: \'zle\' }
];

Answer 1

This is probably more verbose than you want, but you're asking for a slightly complex operation so actual code might be involved (the horror).

My recommendation, with zipObject that's pretty logical:

_.zipObject(_.map(params, 'name'), _.map(params, 'input'));

Another option, more hacky, using fromPairs:

_.fromPairs(_.map(params, function(val) { return [val['name'], val['input']));

The anonymous function shows the hackiness -- I don't believe JS guarantees order of elements in object iteration, so callling .values() won't do.

Answer 2

Another way with lodash

creating pairs, and then either construct a object or ES6 Map easily

_(params).map(v=>[v.name, v.input]).fromPairs().value()

or

_.fromPairs(params.map(v=>[v.name, v.input]))

Here is a working example

var params = [
    { name: 'foo', input: 'bar' },
    { name: 'baz', input: 'zle' }
];

var obj = _(params).map(v=>[v.name, v.input]).fromPairs().value();

console.log(obj);

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.4/lodash.js"></script>

Answer 3

Another way with lodash 4.17.2

_.chain(params)
    .keyBy('name')
    .mapValues('input')
    .value();

or

_.mapValues(_.keyBy(params, 'name'), 'input')

or with _.reduce

_.reduce(
    params,
    (acc, { name, input }) => ({ ...acc, [name]: input }),
    {}
)

Answer 4

This seems like a job for Object.assign:

const output = Object.assign({}, ...params.map(p => ({[p.name]: p.input})));

Edited to wrap as a function similar to OP's, this would be:

const toHash = (array, keyName, valueName) => 
    Object.assign({}, ...array.map(o => ({[o[keyName]]: o[valueName]})));

(Thanks to Ben Steward, good thinking...)

Answer 5

It can also solve without using any lodash function like this:

let paramsVal = [
    { name: 'foo', input: 'bar' },
    { name: 'baz', input: 'zle' }
];
let output = {};

paramsVal.forEach(({name, input})=>{
  output[name] = input;
})


console.log(output);

Answer 6

You can use one liner javascript with array reduce method and ES6 destructuring to convert array of key value pairs to object.

arr.reduce((map, { name, input }) => ({ ...map, [name]: input }), {});