math.js

if (! Number.hasOwnProperty('isSafeInteger')) {
	Number.MAX_SAFE_INTEGER = 2**53 -1;
	Number.MIN_SAFE_INTEGER = -Number.MAX_SAFE_INTEGER;
	Number.isSafeInteger = num => num <= Number.MAX_SAFE_INTEGER && num >= Number.MIN_SAFE_INTEGER;
}

if (! Number.hasOwnProperty('EPSILON')) {
	Number.EPSILON = 2**-52;
}

if (! Math.hasOwnProperty('sign')) {
	Math.sign = x => ((x > 0) - (x < 0)) || +x;
}

if (! Math.hasOwnProperty('trunc')) {
	Math.trunc = x => {
		const n = x - x%1;
		return n===0 && (x<0 || (x===0 && (1/x !== 1/0))) ? -0 : n;
	};
}

if (! Math.hasOwnProperty('expm1')) {
	Math.expm1 = x => Math.exp(x) - 1;
}

if (! Math.hasOwnProperty('hypot')) {
	Math.hypot = (...nums) => Math.sqrt(nums.reduce((sum, num) => sum +  num**2, 0));
}

if (! Math.hasOwnProperty('cbrt')) {
	Math.cbrt = x => x**(1/3);
}

if (! Math.hasOwnProperty('log10')) {
	Math.log10 = x => Math.log(x) * Math.LOG10E;
}

if (! Math.hasOwnProperty('log2')) {
	Math.log2 = x => Math.log(x) * Math.LOG2E;
}

if (! Math.hasOwnProperty('log1p')) {
	Math.log1p = x => Math.log(1 + x);
}

if (! Math.hasOwnProperty('fround')) {
	Math.fround = (function (array) {
		return function(x) {
			return array[0] = x, array[0];
		};
	})(new Float32Array(1));
}

if (! (Math.clamp instanceof Function)) {
	Math.clamp = function(value, min, max) {
		return Math.min(Math.max(value, min), max);
	};
}

/*
 * Question of if it will be `Math.clamp` or `Math.constrain`
 */
if (! (Math.constrain instanceof Function)) {
	Math.constrain = Math.clamp;
}

/**
 * @see https://github.com/tc39/proposal-math-sum
 */
if (! (Math.sumPrecise instanceof Function)) {
	Math.sumPrecise = function sumPrecise(nums) {
		let sum = -0;

		for (const num of nums) {
			if (! Number.isFinite(num)) {
				sum = -0;
				break;
			} else {
				sum += num;
			}
		}

		return sum;
	};
}

/**
 * @deprecated
 */
if(! (Math.sum instanceof Function)) {
	Math.sum = function(...nums) {
		console.warn('Math.sum is deprecated. Please use Math.sumPrecise instead.');
		return Math.sumPrecise(nums);
	};
}