@aeternity/aepp-sdk/es/utils/amount-formatter.js

SDK for the æternity blockchain

import { BigNumber } from 'bignumber.js'

const prefixes = [
  { name: 'exa', magnitude: 18 },
  { name: 'giga', magnitude: 9 },
  { name: '', magnitude: 0 },
  { name: 'pico', magnitude: -12 }
]

const getNearestPrefix = exponent => prefixes.reduce((p, n) => (
  Math.abs(n.magnitude - exponent) < Math.abs(p.magnitude - exponent) ? n : p))

const getLowerBoundPrefix = exponent => prefixes
  .find(p => p.magnitude <= exponent) || prefixes[prefixes.length - 1]

export default (value) => {
  if (!BigNumber.isBigNumber(value)) value = BigNumber(value)

  const { name, magnitude } = (value.e < 0 ? getNearestPrefix : getLowerBoundPrefix)(value.e)
  const v = value
    .shiftedBy(-magnitude)
    .precision(9 + Math.min(value.e - magnitude, 0))
    .toFixed()
  return `${v}${name ? ' ' : ''}${name}`
}