Convert JavaScript array of 2 element arrays into object key value pairs
Lodash has a _.fromPairs
method that does exactly that.
From the documentation:
_.fromPairs([['a', 1], ['b', 2]]);
// => { 'a': 1, 'b': 2 }
Terse version using modern syntax:
let objectify = a => a.reduce( (o,[k,v]) => (o[k]=v,o), {} );
I use this technique as part of a terse query string parser:
// Converts "?foo=bar&j=1&go" into { foo:'bar', j:'1', go:true }
function parseQueryString(qs) {
var q = decodeURIComponent;
return qs.replace(/^\?/,'').split('&').map(s => s.split('='))
.reduce((o,[k,v]) => (o[q(k)] = v?q(v):true, o), {});
}
With Object.fromEntries
, you can convert from Array
to Object
:
var array = [
[1, 'a'],
[2, 'b'],
[3, 'c']
];
var object = Object.fromEntries(array);
console.log(object);
You could indeed use Array.prototype.reduce
:
function objectify(array) {
return array.reduce(function(p, c) {
p[c[0]] = c[1];
return p;
}, {});
}
where p
is the result of the previous iteration, initially {}
, and c
is the current element of the array.
It's unlikely to be any faster than array.forEach
, but it is IMHO cleaner. I don't believe there's any simpler implementation than this.
NB: a function to do exactly this already exists in the Underscore library: _.object(array)