I want to convert the following array:
['a', 'b', 'c']
to the following object:
{a: 'a', b: 'b', c: 'c'}
How do I do it without using loop, ofcourse?
8 Answers
You'll want to use the Array.reduce() method.
The reduce() method executes a reducer function (that you provide) on each member of the array resulting in a single output value.
arr.reduce(callback[, initialValue])
The reduce() callback method takes accumulator and currentValue parameters.
- accumulator: Value is remembered throughout each iteration of the method and ultimately becomes the final returned value.
- currentValue: The current element being processed in the
array.
The {} is supplied as the last argument to reduce() as the initial value to start with. And with each iteration of the Array, we add to it ultimately creating the final Object.
Example: (ES6)
const letters = ['a', 'b', 'c'];
const obj = letters.reduce((accumulator, currentValue) => {
accumulator[currentValue] = currentValue;
return accumulator;
}, {});
console.log(obj);Example: (ES5)
var letters = ['a', 'b', 'c'];
var obj = letters.reduce(function (accumulator, currentValue) {
accumulator[currentValue] = currentValue;
return accumulator;
}, {});
console.log(obj);Reference: Array.prototype.reduce() mozilla documentation.
Comments
You could map objects and join to a single object with Object.assign.
var array = ['a', 'b', 'c'],
object = Object.assign(...array.map(v => ({ [v]: v })));
console.log(object);3 Comments
loveTrumpsHate
Any way to do this without using map?
Nina Scholz
why not with map?
loveTrumpsHate
map is fine but something shorter using spread operator, maybe?
An alternative solution, you can also use the newer Object.fromEntries with map as well.
let arr = ['a', 'b', 'c'];
let obj = Object.fromEntries(arr.map(m => [m,m]));
console.log(obj);
Comments
You may use Array#reduce to get the desired result.
const a = ['a', 'b', 'c'];
const o = a.reduce((s, a) => {
s[a] = a;
return s;
}, {});
console.log(o);
Comments
Use reduce
var arr = ['a', 'b', 'c'];
var obj = arr.reduce(function(obj, value) {
obj[value] = value;
return obj
}, {});
console.log(obj)
Comments
The object.assign() might solve your problem.
Here is an example.
var array = ['a', 'b', 'c'];
Object.assign( {}, array);
// {0: "a", 1: "b", 2: "c"}
The new object will have same index with the array.
If you want the values of the array to be same with the key.
function arrayToObject( array)
{
var object = array.reduce( (obj, value) => {
obj[value] = value;
return obj
}, {});
return object;
}
arrayToObject( ['a', 'b', 'c'])
1 Comment
ikwuje
@trincot thanks for mentioning. I actually thought they were the same,
This is probably the shortest version :
console.log( ['a', 'b', 'c'].reduce((o, v) => (o[v] = v, o), {}) )
Comments
const values = ['a', 'b', 'c'] const objectValues = {...values} =>
const values = ['a', 'b', 'c']
const objectValues = {...values}
console.log(objectValues)
{...['a', 'b', 'c']}results in{0: "a", 1: "b", 2: "c"}. It can't be done without map, reduce, or similar loop