countAs

Counts occurrences of values. 🏃 📼 📦 🌔 📒

Alternatives: count, countAs.

lists.countAs(x, [fm]);
// x:  lists
// fm: map function (v, k, x)
// --> Map {value => count}

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

var x = [['a', 1], ['b', 1], ['c', 2], ['d', 2], ['e', 4]];
entries.countAs(x);
// Map(3) { 1 => 2, 2 => 2, 4 => 1 }

var x = [['a', 1], ['b', 2], ['c', 3], ['d', 4]];
entries.countAs(x, v => v % 2);
// Map(2) { 1 => 2, 0 => 2 }

references

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