Is there some super new ES JavaScript magic that can achieve this ? (I can write a function to achieve this, was just wondering if any new ES202* technique exists )
let arr = [
['cb', ''],
['cb', '34'],
['cb', '35'],
['rb', '1']
];
/*
Required Output :
[['cb', ['34', '35']], ['rb', '1']]
*/
console.log([...new Set(arr.flat(1))])
You could take the upcoming Array#groupBy.
Approach with (own) polyfill.
Array.prototype.groupBy ??= function (callbackfn, thisArg) {
const O = Object(this);
const len = O.length >>> 0;
if (typeof callbackfn !== 'function') throw new TypeError(callbackfn + ' is not a function');
let k = 0;
const groups = {};
while (k < len) {
const Pk = Number(k).toString();
const kValue = O[Pk];
const propertyKey = callbackfn.call(thisArg, kValue, Number(k), O);
(groups[propertyKey] ??= []).push(kValue);
++k;
}
return groups;
};
const
array = [['cb', ''], ['cb', '34'], ['cb', '35'], ['rb', '1']],
result = Object
.entries(array
.filter(([, v]) => v)
.groupBy(([k]) => k)
)
.map(([k, v]) => [k, v.map(([, v]) => v)]);
console.log(result);.as-console-wrapper { max-height: 100% !important; top: 0; }