1.js

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

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

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

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

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

    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);
    });

    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);
        });
    });
});