26 lines
714 B
JavaScript
26 lines
714 B
JavaScript
// @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/round
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module.exports = function (value, exp) {
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// If the exp is undefined or zero...
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if (typeof exp === 'undefined' || +exp === 0) {
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return Math.round(value);
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}
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value = +value;
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exp = +exp;
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// If the value is not a number or the exp is not an integer...
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if (isNaN(value) || !(typeof exp === 'number' && exp % 1 === 0)) {
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return NaN;
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}
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// Shift
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value = value.toString().split('e');
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value = Math.round(+(value[0] + 'e' + (value[1] ? (+value[1] - exp) : -exp)));
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// Shift back
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value = value.toString().split('e');
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return +(value[0] + 'e' + (value[1] ? (+value[1] + exp) : exp));
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}; |