What is a Math API polyfill used for in web development?

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javascriptMath.trunc=Math.trunc || function(x) { return x - (x % 1);};

Math.sign=Math.sign || function(x) { x=Number(x); return (x===0 || isNaN(x)) ? x : x > 0 ? 1 : -1;};

Math.cbrt=Math.cbrt || function(x) { return x > 0 ? Math.pow(x, 1/3) : x <0 ? -Math.pow(-x, 1/3) : 0;};

Math.trunc = Math.trunc || function(x) { return x < 0 ? Math.ceil(x) : Math.floor(x); } Math.sign = Math.sign || function(x) { x = +x; // convert to number if (x === 0 || isNaN(x)) { return x; } return x > 0 ? 1 : -1; } Math.cbrt = Math.cbrt || function(x) { var y = Math.pow(Math.abs(x), 1/3); return x < 0 ? -y : y; }