/**
 * Shorten number to thousands, millions, billions, etc.
 * http://en.wikipedia.org/wiki/Metric_prefix
 *
 * @param {number} num Number to shorten.
 * @param {number} [digits=0] The number of digits to appear after the decimal point.
 * @returns {string|number}
 *
 * @example
 * // returns '12.5k'
 * shortenLargeNumber(12543, 1)
 *
 * @example
 * // returns '-13k'
 * shortenLargeNumber(-12567)
 *
 * @example
 * // returns '51M'
 * shortenLargeNumber(51000000)
 *
 * @example
 * // returns 651
 * shortenLargeNumber(651)
 *
 * @example
 * // returns 0.12345
 * shortenLargeNumber(0.12345)
 */
function shortenLargeNumber(num, digits) {
    var units = ['k', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y'],
        decimal;

    for(var i=units.length-1; i>=0; i--) {
        decimal = Math.pow(1000, i+1);

        if(num <= -decimal || num >= decimal) {
            return +(num / decimal).toFixed(digits) + units[i];
        }
    }

    return num;
}

谢谢@Cos的评论，我删除了Math。round10依赖。

简单通用的方法

可以将COUNT_FORMATS配置对象设置为您想要的长度或长度，这取决于您测试的值范围。

// Configuration const COUNT_FORMATS = [ { // 0 - 999 letter: '', limit: 1e3 }, { // 1,000 - 999,999 letter: 'K', limit: 1e6 }, { // 1,000,000 - 999,999,999 letter: 'M', limit: 1e9 }, { // 1,000,000,000 - 999,999,999,999 letter: 'B', limit: 1e12 }, { // 1,000,000,000,000 - 999,999,999,999,999 letter: 'T', limit: 1e15 } ]; // Format Method: function formatCount(value) { const format = COUNT_FORMATS.find(format => (value < format.limit)); value = (1000 * value / format.limit); value = Math.round(value * 10) / 10; // keep one decimal number, only if needed return (value + format.letter); } // Test: const test = [274, 1683, 56512, 523491, 9523489, 5729532709, 9421032489032]; test.forEach(value => console.log(`${ value } >>> ${ formatCount(value) }`));

一个更普遍的版本:

function nFormatter(num, digits) { const lookup = [ { value: 1, symbol: "" }, { value: 1e3, symbol: "k" }, { value: 1e6, symbol: "M" }, { value: 1e9, symbol: "G" }, { value: 1e12, symbol: "T" }, { value: 1e15, symbol: "P" }, { value: 1e18, symbol: "E" } ]; const rx = /\.0+$|(\.[0-9]*[1-9])0+$/; var item = lookup.slice().reverse().find(function(item) { return num >= item.value; }); return item ? (num / item.value).toFixed(digits).replace(rx, "$1") + item.symbol : "0"; } /* * Tests */ const tests = [ { num: 0, digits: 1 }, { num: 12, digits: 1 }, { num: 1234, digits: 1 }, { num: 100000000, digits: 1 }, { num: 299792458, digits: 1 }, { num: 759878, digits: 1 }, { num: 759878, digits: 0 }, { num: 123, digits: 1 }, { num: 123.456, digits: 1 }, { num: 123.456, digits: 2 }, { num: 123.456, digits: 4 } ]; tests.forEach(function(test) { console.log("nFormatter(" + test.num + ", " + test.digits + ") = " + nFormatter(test.num, test.digits)); });

以下是我对韦伦·弗林的回答的看法。这将删除.0并修复当层不是整数时的未定义。

const SI_SYMBOL = ['', 'k', 'M', 'G', 'T', 'P', 'E'];

abbreviateNumber(num) {
    const tier = Math.floor(Math.log10(num) / 3) || 0;
    let result = '' + num;
    // if zero, we don't need a suffix
    if (tier > 0) {
      // get suffix and determine scale
      const suffix = SI_SYMBOL[tier];
      const scale = Math.pow(10, tier * 3);
      // scale the number
      const scaled = num / scale;
      // format number and add suffix
      result = scaled.toFixed(1).replace('.0', '') + suffix;
    }
    return result;
  }

Waylon flynn的答案的修改版本，支持负指数:

function metric(number) { const SI_SYMBOL = [ ["", "k", "M", "G", "T", "P", "E"], // + ["", "m", "μ", "n", "p", "f", "a"] // - ]; const tier = Math.floor(Math.log10(Math.abs(number)) / 3) | 0; const n = tier < 0 ? 1 : 0; const t = Math.abs(tier); const scale = Math.pow(10, tier * 3); return { number: number, symbol: SI_SYMBOL[n][t], scale: scale, scaled: number / scale } } function metric_suffix(number, precision) { const m = metric(number); return (typeof precision === 'number' ? m.scaled.toFixed(precision) : m.scaled) + m.symbol; } for (var i = 1e-6, s = 1; i < 1e7; i *= 10, s *= -1) { // toggles sign in each iteration console.log(metric_suffix(s * (i + i / 5), 1)); } console.log(metric(0));

预期的输出:

   1.2μ
 -12.0μ
 120.0μ
  -1.2m
  12.0m
-120.0m
   1.2
 -12.0
 120.0
  -1.2k
  12.0k
-120.0k
   1.2M
{ number: 0, symbol: '', scale: 1, scaled: 0 }

您可以使用模仿Python高级字符串格式化PEP3101的d3格式包:

var f = require('d3-format')
console.log(f.format('.2s')(2500)) // displays "2.5k"