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/** * [Sign](https://en.wikipedia.org/wiki/Sign_function) is a function * that extracts the sign of a real number * * @param {number} x input value * @returns {number} sign value either 1, 0 or -1 * @throws {TypeError} if the input argument x is not a number * @private * * @example * sign(2); // => 1 */function sign(x) {    if (typeof x === "number") {        if (x < 0) {            return -1;        } else if (x === 0) {            return 0;        } else {            return 1;        }    } else {        throw new TypeError("not a number");    }}
export default sign;