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function isPositiveZero(value) {
return value === 0 && 1 / value === Infinity;
}
function isNegativeZero(value) {
return value === 0 && 1 / value === -Infinity;
}
test("basic functionality", () => {
expect(Math.sign).toHaveLength(1);
expect(Math.sign(0.0001)).toBe(1);
expect(Math.sign(1)).toBe(1);
expect(Math.sign(42)).toBe(1);
expect(Math.sign(Infinity)).toBe(1);
expect(isPositiveZero(Math.sign(0))).toBeTrue();
expect(isPositiveZero(Math.sign(null))).toBeTrue();
expect(isPositiveZero(Math.sign(""))).toBeTrue();
expect(isPositiveZero(Math.sign([]))).toBeTrue();
expect(Math.sign(-0.0001)).toBe(-1);
expect(Math.sign(-1)).toBe(-1);
expect(Math.sign(-42)).toBe(-1);
expect(Math.sign(-Infinity)).toBe(-1);
expect(isNegativeZero(Math.sign(-0))).toBeTrue();
expect(isNegativeZero(Math.sign(-null))).toBeTrue();
expect(isNegativeZero(Math.sign(-""))).toBeTrue();
expect(isNegativeZero(Math.sign(-[]))).toBeTrue();
expect(Math.sign()).toBeNaN();
expect(Math.sign(undefined)).toBeNaN();
expect(Math.sign([1, 2, 3])).toBeNaN();
expect(Math.sign({})).toBeNaN();
expect(Math.sign(NaN)).toBeNaN();
expect(Math.sign("foo")).toBeNaN();
});
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