我决定在这里扩展@Novellizator的答案，以满足我的需求。我想要一个灵活的函数来处理我的大部分格式化需求，而不需要外部库。

特性

选择使用顺序后缀(k, M等) 选项指定要使用的订单后缀的自定义列表 选项来约束最小和最大顺序 控制小数点后的位数 自动顺序分隔逗号 可选百分比或美元格式 控制在非数字输入的情况下返回什么 适用于负数和无穷数

例子

let x = 1234567.8;
formatNumber(x);  // '1,234,568'
formatNumber(x, {useOrderSuffix: true});  // '1M'
formatNumber(x, {useOrderSuffix: true, decimals: 3, maxOrder: 1});  // '1,234.568k'
formatNumber(x, {decimals: 2, style: '$'});  // '$1,234,567.80'

x = 10.615;
formatNumber(x, {style: '%'});  // '1,062%'
formatNumber(x, {useOrderSuffix: true, decimals: 1, style: '%'});  // '1.1k%'
formatNumber(x, {useOrderSuffix: true, decimals: 5, style: '%', minOrder: 2});  // '0.00106M%'

formatNumber(-Infinity);  // '-∞'
formatNumber(NaN);  // ''
formatNumber(NaN, {valueIfNaN: NaN});  // NaN

函数

/*
 * Return the given number as a formatted string.  The default format is a plain
 * integer with thousands-separator commas.  The optional parameters facilitate
 * other formats:
 *   - decimals = the number of decimals places to round to and show
 *   - valueIfNaN = the value to show for non-numeric input
 *   - style
 *     - '%': multiplies by 100 and appends a percent symbol
 *     - '$': prepends a dollar sign
 *   - useOrderSuffix = whether to use suffixes like k for 1,000, etc.
 *   - orderSuffixes = the list of suffixes to use
 *   - minOrder and maxOrder allow the order to be constrained.  Examples:
 *     - minOrder = 1 means the k suffix should be used for numbers < 1,000
 *     - maxOrder = 1 means the k suffix should be used for numbers >= 1,000,000
 */
function formatNumber(number, {
    decimals = 0,
    valueIfNaN = '',
    style = '',
    useOrderSuffix = false,
    orderSuffixes = ['', 'k', 'M', 'B', 'T'],
    minOrder = 0,
    maxOrder = Infinity
  } = {}) {

  let x = parseFloat(number);

  if (isNaN(x))
    return valueIfNaN;

  if (style === '%')
    x *= 100.0;

  let order;
  if (!isFinite(x) || !useOrderSuffix)
    order = 0;
  else if (minOrder === maxOrder)
    order = minOrder;
  else {
    const unboundedOrder = Math.floor(Math.log10(Math.abs(x)) / 3);
    order = Math.max(
      0,
      minOrder,
      Math.min(unboundedOrder, maxOrder, orderSuffixes.length - 1)
    );
  }

  const orderSuffix = orderSuffixes[order];
  if (order !== 0)
    x /= Math.pow(10, order * 3);

  return (style === '$' ? '$' : '') +
    x.toLocaleString(
      'en-US',
      {
        style: 'decimal',
        minimumFractionDigits: decimals,
        maximumFractionDigits: decimals
      }
    ) +
    orderSuffix +
    (style === '%' ? '%' : '');
}

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 }

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"

一个简短的替代方案:

function nFormatter(num) { const format = [ { value: 1e18, symbol: 'E' }, { value: 1e15, symbol: 'P' }, { value: 1e12, symbol: 'T' }, { value: 1e9, symbol: 'G' }, { value: 1e6, symbol: 'M' }, { value: 1e3, symbol: 'k' }, { value: 1, symbol: '' }, ]; const formatIndex = format.findIndex((data) => num >= data.value); console.log(formatIndex) return (num / format[formatIndex === -1? 6: formatIndex].value).toFixed(2) + format[formatIndex === -1?6: formatIndex].symbol; }

进一步改进Salman's Answer，因为它将nFormatter(33000)返回为33.0K

function nFormatter(num) {
     if (num >= 1000000000) {
        return (num / 1000000000).toFixed(1).replace(/\.0$/, '') + 'G';
     }
     if (num >= 1000000) {
        return (num / 1000000).toFixed(1).replace(/\.0$/, '') + 'M';
     }
     if (num >= 1000) {
        return (num / 1000).toFixed(1).replace(/\.0$/, '') + 'K';
     }
     return num;
}

now nFormatter(33000) = 33K

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"