Add a modulo function to math.js · Pull request #14 · flagon-io/automation-lab

Infinite divisors give NaN: mod(1, Infinity) and mod(-1, Infinity) both return NaN because Math.abs(b) is Infinity and Infinity % Infinity is NaN. This is not in the issue and does not block merge, but it is worth either handling or documenting.

9	9		return a * b;
10	10		}
11	11
	12	+	/** Returns the non-negative remainder of a divided by b; throws RangeError when b is 0. */
	13	+	function mod(a, b) {
	14	+	if (b === 0) {
	15	+	throw new RangeError("mod by zero");
	16	+	}
	17	+	return ((a % b) + Math.abs(b)) % Math.abs(b);
g1t4d ago Infinite divisors give NaN: `mod(1, Infinity)` and `mod(-1, Infinity)` both return NaN because `Math.abs(b)` is Infinity and `Infinity % Infinity` is NaN. This is not in the issue and does not block merge, but it is worth either handling or documenting.
	18	+	}
	19	+
12	20		/** Returns a minus b. */
13	21		function subtract(a, b) {
14	22		return a - b;
⋯
59	67		return Math.sqrt(variance);
60	68		}
61	69
62		−	module.exports = { add, multiply, subtract, divide, power, mean, median, standard_deviation };
	70	+	module.exports = { add, multiply, subtract, divide, mod, power, mean, median, standard_deviation };

6	6		assert.strictEqual(math.multiply(4, 5), 20);
7	7		assert.strictEqual(math.divide(10, 4), 2.5);
8	8		assert.throws(() => math.divide(1, 0), RangeError);
	9	+	assert.strictEqual(math.mod(7, 3), 1);
	10	+	assert.strictEqual(math.mod(-1, 3), 2);
	11	+	assert.strictEqual(math.mod(6, 3), 0);
	12	+	assert.strictEqual(math.mod(-1, -3), 2);
	13	+	assert.throws(() => math.mod(1, 0), RangeError);
9	14		assert.strictEqual(math.power(2, 10), 1024);
10	15		assert.strictEqual(math.power(5, 0), 1);
11	16		assert.throws(() => math.power(2, -1), RangeError);