Metric Prefix

Format numbers using only significant digits and a metric prefix.

prefix(1234567890)
// => '1.23 G'

Install

npm i metric-prefix

basic example

const { prefix } = require('metric-prefix')

prefix(0.123456789)
// => '123 m'

with options

prefix(123456, { unit: 'Hz' })
// => '123 kHz'

prefix(123456, { delimiter: '' })
// => '123k'

prefix(123.456, { precision: 4 })
// => '123.4'

cure bulky options with factory pattern

const prefix = require('metric-prefix')({
  unit: 'W',
  precision: 4,
  delimiter: ''
})

prefix(0.0321) // => '32.10mW'

supported value types

Due to big.js being used internally, all compatible data types can be used.

prefix("100000000000000000000000000")
// => 100 Y

prefix(Big(1e26))
// => 100 Y

Additional Notes

Range

Numbers from 1e-33 to 1e35 can be prefixed. Including non standard prefixes X, W, V. Beyond that a ? will replace the prefix.

Rounding

Prefix floors positive and ceils negative numbers.

Floating Point Arithmetic

In JavaScripts you might encounter situations like

0.3 - 0.1 = 0.19999999999999998

that lead to

prefix(0.3 - 0.1) // => '199 m'

and can be fixed with

prefix(Big(0.3).minus(0.1)) // => '200 m'