javascript:缩短大数字,强制小数位,并选择将1000表示为.001百万

时间:2013-08-09 16:57:32

标签: javascript rounding

我正在努力完成三件事 -

我想缩短大数字并添加K / M / B后缀 我希望能够强制小数位数 我希望能够强制数千表示为百万的小数部分

缩短,舍入到2位小数

  • 1200000 ---->>> 1.2M
  • 1248000 ---->>> 1.25M
  • 248000 ---->>> 248K

缩短,强制2位小数

  • 1200000 ---->>> 1.20M
  • 1248000 ---->>> 1.25M
  • 248000 ---->>> 248.00K

缩短,强制3位小数,强制数千到数百万

  • 1200000 ---->>> 1.200M
  • 1248000 ---->>> 1.248M
  • 248000 ---->>> 0.248M

我有一个javascript函数,我发现它做了很多,除了它不强制小数位数,它不允许我强制数千到数百万

function shortenNumber (num, decimalPlaces) {
var str,
    suffix = '';

decimalPlaces = decimalPlaces || 0;
num = +num;

var factor = Math.pow(10, decimalPlaces);


//99999 -> 99.9K

if (num < 1000) {
    str = num;
} else if (num < 1000000) {
    str = Math.floor(num / (1000 / factor)) / factor;
    suffix = 'K';
} else if (num < 1000000000) {
    str = Math.floor(num / (1000000 / factor)) / factor;
    suffix = 'M';
} else if (num < 1000000000000) {
    str = Math.floor(num / (1000000000 / factor)) / factor;
    suffix = 'B';
} else if (num < 1000000000000000) {
    str = Math.floor(num / (1000000000000 / factor)) / factor;
    suffix = 'T';
}
return str + suffix;
}

所以它完成了第一个要求,部分完成了第二个要求(它将舍入到2个小数位,但如果小数点为0则会丢弃它),但不能将K表示为M的

如何修改此功能以执行此操作(或将其替换为其他功能)?

谢谢!

2 个答案:

答案 0 :(得分:12)

这应该按照你的要求行事:

function abbreviate(number, maxPlaces, forcePlaces, forceLetter) {
  number = Number(number)
  forceLetter = forceLetter || false
  if(forceLetter !== false) {
    return annotate(number, maxPlaces, forcePlaces, forceLetter)
  }
  var abbr
  if(number >= 1e12) {
    abbr = 'T'
  }
  else if(number >= 1e9) {
    abbr = 'B'
  }
  else if(number >= 1e6) {
    abbr = 'M'
  }
  else if(number >= 1e3) {
    abbr = 'K'
  }
  else {
    abbr = ''
  }
  return annotate(number, maxPlaces, forcePlaces, abbr)
}

function annotate(number, maxPlaces, forcePlaces, abbr) {
  // set places to false to not round
  var rounded = 0
  switch(abbr) {
    case 'T':
      rounded = number / 1e12
      break
    case 'B':
      rounded = number / 1e9
      break
    case 'M':
      rounded = number / 1e6
      break
    case 'K':
      rounded = number / 1e3
      break
    case '':
      rounded = number
      break
  }
  if(maxPlaces !== false) {
    var test = new RegExp('\\.\\d{' + (maxPlaces + 1) + ',}$')
    if(test.test(('' + rounded))) {
      rounded = rounded.toFixed(maxPlaces)
    }
  }
  if(forcePlaces !== false) {
    rounded = Number(rounded).toFixed(forcePlaces)
  }
  return rounded + abbr
}

abbreviate(1200000, 2, false, false)
abbreviate(1248000, 2, false, false)
abbreviate(248000, 2, false, false)

abbreviate(1200000, 2, 2, false)
abbreviate(1248000, 2, 2, false)
abbreviate(248000, 2, 2, false)

abbreviate(1200000, 3, 3, 'M')
abbreviate(1248000, 3, 3, 'M')
abbreviate(248000, 3, 3, 'M')

答案 1 :(得分:4)

如果你不反对外部图书馆,那就是Numeral.js