polyfill-service/polyfills/Math/asinh/tests.js

A polyfill combinator

// Returns an implementation-dependent approximation to the inverse hyperbolic sine of x.
// See: https://people.mozilla.org/~jorendorff/es6-draft.html#sec-math.asinh

it("Should return NaN if the parameter is NaN", function() {
	var x = Math.asinh(NaN);
	expect(x.toString()).to.be(NaN.toString());
});

it("Should return 0 if the parameter is 0", function() {
	var x = Math.asinh(0);
	expect(x).to.be(0);
});

it("Should return Number.POSITIVE_INFINITY if the parameter is Number.POSITIVE_INFINITY", function() {
	var x = Math.asinh(Number.POSITIVE_INFINITY);
	expect(x).to.be(Number.POSITIVE_INFINITY);
});

it("Should return Number.NEGATIVE_INFINITY if the parameter is Number.NEGATIVE_INFINITY", function() {
	var x = Math.asinh(Number.NEGATIVE_INFINITY);
	expect(x).to.be(Number.NEGATIVE_INFINITY);
});

it("Should approximate the inverse hyperbolic sine of the parameter", function() {
	var x = Math.asinh(0.5);
	expect(x).to.be.within(0.4, 0.5);
});