How to convert array to object in Javascript?

Question

I have the following array:

const x = [
    {event: "oninput", action: ""},
    {event: "onfocus", action: ""}
]

Following is the desired output:

// event: action
{
    oninput: "",
    onfocus: ""
}

I tried the following which didn't really work:

const x = [
    {event: "oninput", action: ""},
    {event: "onfocus", action: ""}
]

console.log({...x.map(y => {return {[y.event]: y.action}})})

Possible duplicate of [Convert Array to Object](https://stackoverflow.com/questions/4215737/convert-array-to-object) — holydragon, Jan 11 '19 at 08:05
`.map` returns an array, spreading it into an object will result in numeric-indexed properties. — CertainPerformance, Jan 11 '19 at 08:08

Nina Scholz · Accepted Answer · 2019-01-11T08:27:52.863

6

You could use Object.assign and map the objects. This collects all objects and assign it to a single object.

const x = [
    { event: "oninput", action: "" },
    { event: "onfocus", action: "" }
];

console.log(Object.assign(...x.map(({ event, action }) => ({ [event]: action }))));

edited Jan 11 '19 at 08:27

answered Jan 11 '19 at 08:06

Nina Scholz

376,160
25
347
392

score 0 · Answer 2 · answered Jan 11 '19 at 08:46

You can use reduce to build a new object. It also gives compatibility back to ECMAScript 2011:

var x = [
    {event: "oninput", action: ""},
    {event: "onfocus", action: ""}
];

var o = x.reduce((acc, obj) => {acc[obj.event] = obj.action; return acc}, {});

console.log(o);

score 0 · Answer 3 · answered Jan 11 '19 at 08:48

0

Different approach:

const x = [
    {event: "oninput", action: ""},
    {event: "onfocus", action: ""}
]
let newObj = {}
x.forEach(obj => {
    newObj[obj.event] = obj.action
})


console.log(newObj)
// returns { oninput: '', onfocus: '' }

answered Jan 11 '19 at 08:48

Happy Machine

987
8
30

How to convert array to object in Javascript?

3 Answers3