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| author | ruki <waruqi@gmail.com> | 2018-11-08 00:38:48 +0800 |
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| committer | ruki <waruqi@gmail.com> | 2018-11-07 21:53:09 +0800 |
| commit | 26105034da4fcce7ac883c899d781f016559310d (patch) | |
| tree | c459a5dc4e3aa0972d9919033ece511ce76dd129 /node_modules/@babel/plugin-proposal-numeric-separator/README.md | |
| parent | 2c77f00f1a7ecb6c8192f9c16d3b2001b254a107 (diff) | |
| download | xmake-docs-26105034da4fcce7ac883c899d781f016559310d.tar.gz xmake-docs-26105034da4fcce7ac883c899d781f016559310d.zip | |
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diff --git a/node_modules/@babel/plugin-proposal-numeric-separator/README.md b/node_modules/@babel/plugin-proposal-numeric-separator/README.md new file mode 100644 index 00000000..4dcde023 --- /dev/null +++ b/node_modules/@babel/plugin-proposal-numeric-separator/README.md @@ -0,0 +1,114 @@ +# @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 + +```js +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 + +```js +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 + +```js +// 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 + +```sh +npm install --save-dev @babel/plugin-proposal-numeric-separator +``` + +## Usage + +### Via `.babelrc` (Recommended) + +**.babelrc** + +```json +{ + "plugins": ["@babel/plugin-proposal-numeric-separator"] +} +``` + +### Via CLI + +```sh +babel --plugins @babel/plugin-proposal-numeric-separator script.js +``` + +### Via Node API + +```javascript +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"`](http://babeljs.io/docs/plugins/transform-literals/) plugin: + +> `@babel/plugin-transform-literals` is already included in [@babel/preset-env](https://github.com/babel/babel/tree/master/packages/babel-preset-env) and @babel/preset-es2015. + +### Via `.babelrc` (Recommended) + +**.babelrc** + +```json +{ + "presets": ["@babel/preset-env"], + "plugins": ["@babel/plugin-proposal-numeric-separator"] +} +{ + "plugins": ["@babel/plugin-proposal-numeric-separator", "@babel/plugin-transform-literals"] +} +``` + +## References + +* [Proposal: Numeric Separators](https://github.com/samuelgoto/proposal-numeric-separator) |
