使用最大余额法计算百分比

[akaxiaok]

getPercentWithPrecision 如果用了 echarts 的话 可以直接用

import { getPercentWithPrecision } from 'echarts/src/util/number';

[akaxiaok]

/**
 * Get a data of given precision, assuring the sum of percentages
 * in valueList is 1.
 * The largest remainer method is used.
 * https://en.wikipedia.org/wiki/Largest_remainder_method
 *
 * @param {Array.<number>} valueList a list of all data
 * @param {number} idx index of the data to be processed in valueList
 * @param {number} precision integer number showing digits of precision
 * @return {number} percent ranging from 0 to 100
 */
export function getPercentWithPrecision(valueList, idx, precision) {
    if (!valueList[idx]) {
        return 0;
    }

    var sum = zrUtil.reduce(valueList, function (acc, val) {
        return acc + (isNaN(val) ? 0 : val);
    }, 0);
    if (sum === 0) {
        return 0;
    }

    var digits = Math.pow(10, precision);
    var votesPerQuota = zrUtil.map(valueList, function (val) {
        return (isNaN(val) ? 0 : val) / sum * digits * 100;
    });
    var targetSeats = digits * 100;

    var seats = zrUtil.map(votesPerQuota, function (votes) {
        // Assign automatic seats.
        return Math.floor(votes);
    });
    var currentSum = zrUtil.reduce(seats, function (acc, val) {
        return acc + val;
    }, 0);

    var remainder = zrUtil.map(votesPerQuota, function (votes, idx) {
        return votes - seats[idx];
    });

    // Has remainding votes.
    while (currentSum < targetSeats) {
        // Find next largest remainder.
        var max = Number.NEGATIVE_INFINITY;
        var maxId = null;
        for (var i = 0, len = remainder.length; i < len; ++i) {
            if (remainder[i] > max) {
                max = remainder[i];
                maxId = i;
            }
        }

        // Add a vote to max remainder.
        ++seats[maxId];
        remainder[maxId] = 0;
        ++currentSum;
    }

    return seats[idx] / digits;
}