minify-numeric-literal

Minifies JavaScript numeric literals. Suitable for use in JavaScript source code minifiers. Input a numeric literal, output the shortest one possible.

Installation

npm install minify-numeric-literal

Usage

import mnl from 'minify-numeric-literal'

// Some literals are unchanged
mnl('0')                       // "0"
mnl('126')                     // "126"
mnl('100845')                  // "100845"

// Always omit a leading 0 before the decimal point
mnl('0.00783')                 // ".00783", saves 1 character

// Use exponents when appropriate
mnl('0.000783')                // "783e-6", saves 2 characters
mnl('9000')                    // "9e3", saves 1 character
mnl('1000000000000')           // "1e12", saves 9 characters

// Lose the exponent when appropriate
mnl('1.476925632985436e+10')   // "14769256329.85436", saves 4 characters

// Use hex when appropriate
mnl('10000000000000002')       // "0x2386f26fc10002", saves 1 character

// Use 0xFFFF...F when it works out the same as 0x10000...0
mnl('72057594037927936')       // "0xffffffffffffff", saves 1 character

// Lose the decimal point when possible
mnl('1.476925632985436e99')    // "1476925632985436e84", saves 1 character
mnl('2.2250738585072036e-208') // "22250738585072036e-224", saves 1 character

// Cannot produce meaningful output unless the input is a numeric literal
mnl('-7')                      // null
mnl('-0')                      // null
mnl('NaN')                     // null
mnl('Infinity')                // null
mnl('asdf')                    // null
mnl(371000)                    // null

If you want to pass in a number directly:

import { fromNumber } from 'minify-numeric-literal'

// Works as normal
fromNumber(9000)      // "9e3"

// Cannot produce meaningful output unless the input is a non-negative number
fromNumber(-7)        // null
fromNumber(-0)        // null
fromNumber(-Infinity) // null
fromNumber(NaN)       // null
fromNumber('asdf')    // null

// But since there is a numeric literal for `Infinity`...
fromNumber(Infinity)  // "2e308"

• For an arbitrary number x, the longest possible output from String(x) is 24 characters e.g. '-2.2250738585072036e-208'.
• For a non-negative number x, the longest possible output from String(x) is 23 characters e.g. '2.2250738585072036e-208'.
• For a non-negative number x, the longest possible output from fromNumber(x) is 22 characters e.g. '22250738585072036e-224'.

FAQ

What if my numeric literal is being used in a method call context e.g. 90.0.toString()?

In this situation, mnl('90.0') or fromNumber(90.0) both return '90', which is no good for your purpose because 90.toString() is syntactically invalid JavaScript.

You may pass in the methodCallContext flag, i.e. mnl('90.0', true) or mnl.fromNumber(90.0, true). The result returned is 90., eventually resulting in the syntactically valid 90..toString().

Why not accept negative numbers?

JavaScript does not have negative numeric literals. A JavaScript source code parser encountering an expression like -9000 should return a unary negation operator (-) followed by a non-negative numeric literal 9000, the latter of which mnl accepts.

Why not accept 'Infinity' or 'NaN'?

mnl only accepts numeric literals, which 'Infinity' and 'NaN' are not.

fromNumber accepts numbers but can still only return numeric literals. In the case of -Infinity and NaN this is not possible, but Infinity can be represented by a numeric literal such as '2e308', which we return.