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- "use strict";
-
- var exp = Math.exp;
-
- module.exports = function (value) {
- var num1, num2;
- if (isNaN(value)) return NaN;
- value = Number(value);
- if (value === 0) return value;
- if (value === Infinity) return 1;
- if (value === -Infinity) return -1;
- num1 = exp(value);
- if (num1 === Infinity) return 1;
- num2 = exp(-value);
- if (num2 === Infinity) return -1;
- return (num1 - num2) / (num1 + num2);
- };
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