WorkshopPart1.js

describe("Part 1", function () {
    describe("add", function() {
        it("calculates that 3 + 4 = 7", function () {
            expect(add(3, 4)).toBe(7);
        });
    });

    describe("mul", function() {
        it("calculates that 3 * 4 = 12", function () {
            expect(mul(3, 4)).toBe(12);
        });
    });

    describe("identityf", function () {

        it("creates a function that returns its argument", function () {
            var idf3 = identityf(3);

            expect(idf3()).toBe(3);
        });
    });

    describe("addf", function () {
        it("adds two consecutive calls arguments", function () {
            expect(addf(3)(4)).toBe(7);
        });
    });

    describe("applyf", function () {
        it("applyf takes a function and returns it so it can be applied to two consec args", function () {
            expect(applyf(add)(3)(4)).toBe(7);
            expect(applyf(mul)(5)(6)).toBe(30);
        });
    });

    describe("curry", function () {
        it("curries add with 3", function () {
            var add3 = curry(add, 3);
            expect(add3(4)).toBe(7);
        });
    });


    describe("show three ways to implement inc function", function () {
        it("curry 1", function () {
            var inc = curry(add, 1);
            expect(inc(4)).toBe(5);
            expect(inc(inc(4))).toBe(6);
        });

        it("addf", function () {
            var inc = addf(1);
            expect(inc(4)).toBe(5);
            expect(inc(inc(4))).toBe(6);
        });

        it("applyf", function () {
            var inc = applyf(add)(1);
            expect(inc(4)).toBe(5);
            expect(inc(inc(4))).toBe(6);
        });
    });

    describe("twice converts a binary to a unary that uses the same arg twice", function() {
        it("should double", function() {
           var doubl = twice(add);

            expect(doubl(2)).toBe(4);
            expect(doubl(123)).toBe(246);
        });
    });

});