fn-compose/test/index.js

compose an arbitrary number of functions from right to left.

var test = require('tap').test,
    compose = require('../');

test('should allow single function', function(t){
    t.plan(1);
    var someFunc = function someFunc(){ return 'foo'},
        result = compose(someFunc);

    t.equals(result(), 'foo');
});

test('should compose two functions', function(t){
    t.plan(1);
    var mul = function mul2(a){ return a * 2 },
        sub = function sub1(a){ return a - 1 },
        composed = compose(sub, mul),
        result = composed(5);

    t.equals(result, 9);
});

test('should compose more than two functions', function(t){
    t.plan(1);
    var mul = function mul2(a){ return a * 2 },
        sub = function sub1(a){ return a - 1 },
        composed = compose(mul, sub, mul),
        result = composed(5);

    t.equals(result, 18);
})

test('should can compose ltr as well', function(t){
    t.plan(1);
    var mul = function mul2(a){ return a * 2 },
        sub = function sub1(a){ return a - 1 },
        composed = compose.ltr(sub, mul),
        result = composed(5);

    t.equals(result, 8);
})