What Is The Equivalent Of Python Any() And All() Functions In JavaScript?

Python does has built in functions any() and all(), which are applied on a list(array in JavaScript) as following- any(): Return True if any element of the iterable is true. If the

Solution 1:

The Python documentation gives you pure-python equivalents for both functions; they are trivial to translate to JavaScript:

function any(iterable) {
    for (var index = 0; index < iterable.length; index++) {
        if (iterable[index]) return true;
    }
    return false;
}

and

function all(iterable) {
    for (var index = 0; index < iterable.length; index++) {
        if (!iterable[index]) return false;
    }
    return true;
}

Recent browser versions (implementing ECMAScript 5.1, Firefox 1.5+, Chrome, Edge 12+ and IE 9) have native support in the form of Array.some and Array.every; these take a callback that determines if something is 'true' or not:

some_array.some((elem) => !!elem );
some_array.every((elem) => !!elem );

The Mozilla documentation I linked to has polyfills included to recreate these two methods in other JS implementations.

Solution 2:

You can use lodash.

lodash.every is equivalent to all

lodash.some is equivalent to any

Solution 3:

Build-in function some is equivalent to any I suppose.

const array = [1, 2, 3, 4, 5];

const even = function(element) {
  // checks whether an element is even
  return element % 2 === 0;
};

console.log(array.some(even));
// expected output: true

You can read more in the docs