Convert long number into abbreviated string in JavaScript, with a special shortness requirement

Question

In JavaScript, how would one write a function that converts a given [edit: positive integer] number (below 100 billion) into a 3-letter abbreviation -- where 0-9 an

Answer 1

Intl is the Javascript standard 'package' for implemented internationalized behaviours. Intl.NumberFormatter is specifically the localized number formatter. So this code actually respects your locally configured thousands and decimal separators.

intlFormat(num) {
    return new Intl.NumberFormat().format(Math.round(num*10)/10);
}

abbreviateNumber(value) {
    let num = Math.floor(value);
    if(num >= 1000000000)
        return this.intlFormat(num/1000000000)+'B';
    if(num >= 1000000)
        return this.intlFormat(num/1000000)+'M';
    if(num >= 1000)
        return this.intlFormat(num/1000)+'k';
    return this.intlFormat(num);
}

abbreviateNumber(999999999999) // Gives 999B

Related question: Abbreviate a localized number in JavaScript for thousands (1k) and millions (1m)

Answer 2

A lot of answers on this thread get rather complicated, using Math objects, map objects, for-loops, etc. But those approaches don't actually improve the design very much - they introduce more lines of code, more complexity, and more memory overhead. After evaluating several approaches, I think the manual approach is the easiest to understand, and provides the highest performance.

const formatCash = n => {
  if (n < 1e3) return n;
  if (n >= 1e3 && n < 1e6) return +(n / 1e3).toFixed(1) + "K";
  if (n >= 1e6 && n < 1e9) return +(n / 1e6).toFixed(1) + "M";
  if (n >= 1e9 && n < 1e12) return +(n / 1e9).toFixed(1) + "B";
  if (n >= 1e12) return +(n / 1e12).toFixed(1) + "T";
};

console.log(formatCash(1235000));

Answer 3

            function converse_number (labelValue) {

                    // Nine Zeroes for Billions
                    return Math.abs(Number(labelValue)) >= 1.0e+9

                    ? Math.abs(Number(labelValue)) / 1.0e+9 + "B"
                    // Six Zeroes for Millions 
                    : Math.abs(Number(labelValue)) >= 1.0e+6

                    ? Math.abs(Number(labelValue)) / 1.0e+6 + "M"
                    // Three Zeroes for Thousands
                    : Math.abs(Number(labelValue)) >= 1.0e+3

                    ? Math.abs(Number(labelValue)) / 1.0e+3 + "K"

                    : Math.abs(Number(labelValue));

                }

alert(converse_number(100000000000));

Answer 4

Here's what I think is a fairly elegant solution. It does not attempt to deal with negative numbers:

const COUNT_ABBRS = [ '', 'K', 'M', 'G', 'T', 'P', 'E', 'Z', 'Y' ];

function formatCount(count, withAbbr = false, decimals = 2) {
    const i     = 0 === count ? count : Math.floor(Math.log(count) / Math.log(1000));
    let result  = parseFloat((count / Math.pow(1000, i)).toFixed(decimals));
    if(withAbbr) {
        result += `${COUNT_ABBRS[i]}`; 
    }
    return result;
}

Examples:

   formatCount(1000, true);
=> '1k'
   formatCount(100, true);
=> '100'
   formatCount(10000, true);
=> '10k'
   formatCount(10241, true);
=> '10.24k'
   formatCount(10241, true, 0);
=> '10k'
   formatCount(10241, true, 1)
=> '10.2k'
   formatCount(1024111, true, 1)
=> '1M'
   formatCount(1024111, true, 2)
=> '1.02M'

Answer 5

Code

const SI_PREFIXES = [
  { 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 abbreviateNumber = (number) => {
  if (number === 0) return number

  const tier = SI_PREFIXES.filter((n) => number >= n.value).pop()
  const numberFixed = (number / tier.value).toFixed(1)

  return `${numberFixed}${tier.symbol}`
}

abbreviateNumber(2000) // "2.0k"
abbreviateNumber(2500) // "2.5k"
abbreviateNumber(255555555) // "255.6M"

Test:

import abbreviateNumber from './abbreviate-number'

test('abbreviateNumber', () => {
  expect(abbreviateNumber(0)).toBe('0')
  expect(abbreviateNumber(100)).toBe('100')
  expect(abbreviateNumber(999)).toBe('999')

  expect(abbreviateNumber(1000)).toBe('1.0k')
  expect(abbreviateNumber(100000)).toBe('100.0k')
  expect(abbreviateNumber(1000000)).toBe('1.0M')
  expect(abbreviateNumber(1e6)).toBe('1.0M')
  expect(abbreviateNumber(1e10)).toBe('10.0G')
  expect(abbreviateNumber(1e13)).toBe('10.0T')
  expect(abbreviateNumber(1e16)).toBe('10.0P')
  expect(abbreviateNumber(1e19)).toBe('10.0E')

  expect(abbreviateNumber(1500)).toBe('1.5k')
  expect(abbreviateNumber(1555)).toBe('1.6k')

  expect(abbreviateNumber(undefined)).toBe('0')
  expect(abbreviateNumber(null)).toBe(null)
  expect(abbreviateNumber('100')).toBe('100')
  expect(abbreviateNumber('1000')).toBe('1.0k')
})

Answer 6

I think you cant try this numeraljs/

If you want convert 1000 to 1k

console.log(numeral(1000).format('0a'));

and if you want convert 123400 to 123.4k try this

console.log(numeral(123400).format('0.0a'));