count - nodef/extra-lists GitHub Wiki

Count values which satisfy a test.

Alternatives: count, countAs.

function count(x, ft)
// x:  lists
// ft: test function (v, k, x)

const xlists = require('extra-lists');

var x = ['a', 'b', 'c', 'd', 'e'], [1, 1, 2, 2, 4](/nodef/extra-lists/wiki/'a',-'b',-'c',-'d',-'e'],-[1,-1,-2,-2,-4);
xlists.count(x, v => v % 2 === 1);
// → 2

xlists.count(x, v => v % 2 === 0);
// → 3

References