31 lines
1.0 KiB
JavaScript
31 lines
1.0 KiB
JavaScript
// works as described on http://stackoverflow.com/a/13483710
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function sumsUpTo100(percentages) {
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return percentages.map((p) => Math.floor(p)).reduce((a, b) => a + b) === 100;
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}
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export default function (percentages) {
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let decimals = percentages.map((a) => a % 1);
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const sumOfDecimals = Math.ceil(decimals.reduce((a, b) => a + b));
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// compensate error by adding 1 to n items with the greatest decimal part
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for (let i = 0, max = decimals.length; i < sumOfDecimals && i < max; i++) {
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// find the greatest item in the decimals array, set it to 0,
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// and increase the corresponding item in the percentages array by 1
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let greatest = 0;
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let index = 0;
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for (let j = 0; j < decimals.length; j++) {
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if (decimals[j] > greatest) {
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index = j;
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greatest = decimals[j];
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}
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}
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++percentages[index];
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decimals[index] = 0;
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// quit early when there is a rounding issue
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if (sumsUpTo100(percentages)) {
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break;
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}
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}
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return percentages.map((p) => Math.floor(p));
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}
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