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  • License MIT

Remove numeric separators from Decimal, Binary, Hex and Octal literals

Package Exports

  • @babel/plugin-proposal-numeric-separator

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@babel/plugin-proposal-numeric-separator) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

@babel/plugin-proposal-numeric-separator

This plugin allows Babel to transform Decimal, Binary, Hex and Octal literals containing Numeric Literal Separator to their non-separated form.

Example

Decimal Literals

let budget = 1_000_000_000_000;

// What is the value of `budget`? It's 1 trillion!
//
// Let's confirm:
console.log(budget === 10 ** 12); // true

Binary Literals

let nibbles = 0b1010_0001_1000_0101;

// Is bit 7 on? It sure is!
// 0b1010_0001_1000_0101
//             ^
//
// We can double check:
console.log(!!(nibbles & (1 << 7))); // true

Hex Literal

// Messages are sent as 24 bit values, but should be
// treated as 3 distinct bytes:
let message = 0xA0_B0_C0;

// What's the value of the upper most byte? It's A0, or 160.
// We can confirm that:
let a = (message >> 16) & 0xFF;
console.log(a.toString(16), a); // a0, 160

// What's the value of the middle byte? It's B0, or 176.
// Let's just make sure...
let b = (message >> 8) & 0xFF;
console.log(b.toString(16), b); // b0, 176

// What's the value of the lower most byte? It's C0, or 192.
// Again, let's prove that:
let c = message & 0xFF;
console.log(c.toString(16), b); // c0, 192

Octal Literal

hand wave emoji

Octals are great for permissions, but also look better when represented in 0o0000 form. No real benefit with separators here.

Installation

npm install --save-dev @babel/plugin-proposal-numeric-separator

Usage

.babelrc

{
  "plugins": ["@babel/plugin-proposal-numeric-separator"]
}

Via CLI

babel --plugins @babel/plugin-proposal-numeric-separator script.js

Via Node API

require("@babel/core").transform("code", {
  plugins: ["@babel/plugin-proposal-numeric-separator"]
});

Additional Information

If you need to further compile ES2015 Decimal, Binary, Hex and Octal number representations to their pre-ES2015 numeric literal form, add the "@babel/plugin-transform-literals" plugin:

@babel/plugin-transform-literals is already included in @babel/preset-env and @babel/preset-es2015.

.babelrc

{
  "presets": ["@babel/preset-env"],
  "plugins": ["@babel/plugin-proposal-numeric-separator"]
}
{
  "plugins": ["@babel/plugin-proposal-numeric-separator", "@babel/plugin-transform-literals"]
}

References