countAs - nodef/extra-object GitHub Wiki

Count occurrences of values.

Similar: count, countAs.

function countAs(x, fm)
// x:  an object
// fm: map function (v, k, x)

const object = require('extra-object');

var x = {a: 1, b: 1, c: 2, d: 2, e: 4};
object.countAs(x);
// → Map(3) { 1 => 2, 2 => 2, 4 => 1 }

var x = {a: 1, b: 2, c: 3, d: 4};
object.countAs(x, v => v % 2);
// → Map(2) { 1 => 2, 0 => 2 }

References