如果你喜欢，就把功劳归于韦伦·弗林

这比他处理负数和“。0”的情况。

循环和“如果”情况越少，IMO就越好。

function abbreviateNumber(number) {
    const SI_POSTFIXES = ["", "k", "M", "G", "T", "P", "E"];
    const sign = number < 0 ? '-1' : '';
    const absNumber = Math.abs(number);
    const tier = Math.log10(absNumber) / 3 | 0;
    // if zero, we don't need a prefix
    if(tier == 0) return `${absNumber}`;
    // get postfix and determine scale
    const postfix = SI_POSTFIXES[tier];
    const scale = Math.pow(10, tier * 3);
    // scale the number
    const scaled = absNumber / scale;
    const floored = Math.floor(scaled * 10) / 10;
    // format number and add postfix as suffix
    let str = floored.toFixed(1);
    // remove '.0' case
    str = (/\.0$/.test(str)) ? str.substr(0, str.length - 2) : str;
    return `${sign}${str}${postfix}`;
}

jsFiddle测试用例-> https://jsfiddle.net/qhbrz04o/9/

进一步改进@Yash的回答，支持负数:

function nFormatter(num) {
    isNegative = false
    if (num < 0) {
        isNegative = true
    }
    num = Math.abs(num)
    if (num >= 1000000000) {
        formattedNumber = (num / 1000000000).toFixed(1).replace(/\.0$/, '') + 'G';
    } else if (num >= 1000000) {
        formattedNumber =  (num / 1000000).toFixed(1).replace(/\.0$/, '') + 'M';
    } else  if (num >= 1000) {
        formattedNumber =  (num / 1000).toFixed(1).replace(/\.0$/, '') + 'K';
    } else {
        formattedNumber = num;
    }   
    if(isNegative) { formattedNumber = '-' + formattedNumber }
    return formattedNumber;
}

nFormatter(-120000)
"-120K"
nFormatter(120000)
"120K"

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"

ES2020在Intl中增加了对此的支持。使用如下表示法:

let formatter = Intl。NumberFormat('en'，{符号:'紧凑'}); //示例1 让million = formatter.format(1e6); //示例2 Let billion = formatter.format(1e9); / /打印 console.log(million == '1M'， billion == '1B');

注意如上所示，第二个示例生成1B而不是1G。 NumberFormat规格:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat/NumberFormat https://tc39.es/ecma402#numberformat-objects

注意，目前并不是所有的浏览器都支持ES2020，所以你可能需要这个 Polyfill: https://formatjs.io/docs/polyfills/intl-numberformat

改进@tfmontague的答案，进一步格式化小数点。33.0k到33k

largeNumberFormatter(value: number): any {
   let result: any = value;

   if (value >= 1e3 && value < 1e6) { result = (value / 1e3).toFixed(1).replace(/\.0$/, '') + 'K'; }
   if (value >= 1e6 && value < 1e9) { result = (value / 1e6).toFixed(1).replace(/\.0$/, '') + 'M'; }
   if (value >= 1e9) { result = (value / 1e9).toFixed(1).replace(/\.0$/, '') + 'T'; }

   return result;
}

这是非常优雅的。

function formatToUnits(number, precision) {
  const abbrev = ['', 'k', 'm', 'b', 't'];
  const unrangifiedOrder = Math.floor(Math.log10(Math.abs(number)) / 3)
  const order = Math.max(0, Math.min(unrangifiedOrder, abbrev.length -1 ))
  const suffix = abbrev[order];

  return (number / Math.pow(10, order * 3)).toFixed(precision) + suffix;
}

formatToUnits(12345, 2)
==> "12.35k"
formatToUnits(0, 3)
==> "0.000"