TypeScript recursive power function

2014-12-24 (Wednesday) | 100 words (~1 minutes reading)

This is a power(base, exponent) function in TypeScript that uses recursion instead of the Math.pow() function.

function power(base: number, exponent: number): number {
    if (exponent === 0) {
        return 1;
    }
    return base * power(base, exponent - 1);
}

Jest tests:

describe("power", () => {
    test("2^x", () => {
        expect(power(2, 0)).toBe(1);
        expect(power(2, 1)).toBe(2);
        expect(power(2, 2)).toBe(4);
        expect(power(2, 3)).toBe(8);
        expect(power(2, 4)).toBe(16);
    })

    test("3^x", () => {
        expect(power(3, 0)).toBe(1);
        expect(power(3, 1)).toBe(3);
        expect(power(3, 2)).toBe(9);
        expect(power(3, 3)).toBe(27);
        expect(power(3, 4)).toBe(81);
    })
})

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