count

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]];
entries.count(x, v => v % 2 === 1);
// → 2

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

References

• List-Extra.count: elm
• _.countBy: lodash
• Array.count: sugarjs
• count-iterable-values: @zeke