count - nodef/extra-entries GitHub Wiki

Count values which satisfy a test.

Alternatives: count, countAs.

function count(x, ft)
// x:  entries
// ft: test function (v, k, x)
const entries = require('extra-entries');

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

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

References