lepu-test-platform-web/node_modules/json5/README.md

287 lines
8.7 KiB
Markdown
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

# JSON5 Modern JSON
[![Build Status](https://travis-ci.org/json5/json5.svg)](https://travis-ci.org/json5/json5)
JSON is an excellent data format, but we think it can be better.
**JSON5 is a proposed extension to JSON** that aims to make it easier for
*humans to write and maintain* by hand. It does this by adding some minimal
syntax features directly from ECMAScript 5.
JSON5 remains a **strict subset of JavaScript**, adds **no new data types**,
and **works with all existing JSON content**.
JSON5 is *not* an official successor to JSON, and JSON5 content may *not*
work with existing JSON parsers. For this reason, JSON5 files use a new .json5
extension. *(TODO: new MIME type needed too.)*
The code here is a **reference JavaScript implementation** for both Node.js
and all browsers. Its based directly off of Douglas Crockfords own [JSON
implementation][json_parse.js], and its both robust and secure.
## Why
JSON isnt the friendliest to *write*. Keys need to be quoted, objects and
arrays cant have trailing commas, and comments arent allowed — even though
none of these are the case with regular JavaScript today.
That was fine when JSONs goal was to be a great data format, but JSONs usage
has expanded beyond *machines*. JSON is now used for writing [configs][ex1],
[manifests][ex2], even [tests][ex3] — all by *humans*.
[ex1]: http://plovr.com/docs.html
[ex2]: https://www.npmjs.org/doc/files/package.json.html
[ex3]: http://code.google.com/p/fuzztester/wiki/JSONFileFormat
There are other formats that are human-friendlier, like YAML, but changing
from JSON to a completely different format is undesirable in many cases.
JSON5s aim is to remain close to JSON and JavaScript.
## Features
The following is the exact list of additions to JSONs syntax introduced by
JSON5. **All of these are optional**, and **all of these come from ES5**.
### Objects
- Object keys can be unquoted if theyre valid [identifiers][mdn_variables].
Yes, even reserved keywords (like `default`) are valid unquoted keys in ES5
[[§11.1.5](http://es5.github.com/#x11.1.5), [§7.6](http://es5.github.com/#x7.6)].
([More info](https://mathiasbynens.be/notes/javascript-identifiers))
*(TODO: Unicode characters and escape sequences arent yet supported in this
implementation.)*
- Object keys can also be single-quoted.
- Objects can have trailing commas.
[mdn_variables]: https://developer.mozilla.org/en/Core_JavaScript_1.5_Guide/Core_Language_Features#Variables
### Arrays
- Arrays can have trailing commas.
### Strings
- Strings can be single-quoted.
- Strings can be split across multiple lines; just prefix each newline with a
backslash. [ES5 [§7.8.4](http://es5.github.com/#x7.8.4)]
### Numbers
- Numbers can be hexadecimal (base 16).
- Numbers can begin or end with a (leading or trailing) decimal point.
- Numbers can include `Infinity`, `-Infinity`, `NaN`, and `-NaN`.
- Numbers can begin with an explicit plus sign.
### Comments
- Both inline (single-line) and block (multi-line) comments are allowed.
## Example
The following is a contrived example, but it illustrates most of the features:
```js
{
foo: 'bar',
while: true,
this: 'is a \
multi-line string',
// this is an inline comment
here: 'is another', // inline comment
/* this is a block comment
that continues on another line */
hex: 0xDEADbeef,
half: .5,
delta: +10,
to: Infinity, // and beyond!
finally: 'a trailing comma',
oh: [
"we shouldn't forget",
'arrays can have',
'trailing commas too',
],
}
```
This implementations own [package.json5](package.json5) is more realistic:
```js
// This file is written in JSON5 syntax, naturally, but npm needs a regular
// JSON file, so compile via `npm run build`. Be sure to keep both in sync!
{
name: 'json5',
version: '0.5.0',
description: 'JSON for the ES5 era.',
keywords: ['json', 'es5'],
author: 'Aseem Kishore <aseem.kishore@gmail.com>',
contributors: [
// TODO: Should we remove this section in favor of GitHub's list?
// https://github.com/aseemk/json5/contributors
'Max Nanasy <max.nanasy@gmail.com>',
'Andrew Eisenberg <andrew@eisenberg.as>',
'Jordan Tucker <jordanbtucker@gmail.com>',
],
main: 'lib/json5.js',
bin: 'lib/cli.js',
files: ["lib/"],
dependencies: {},
devDependencies: {
gulp: "^3.9.1",
'gulp-jshint': "^2.0.0",
jshint: "^2.9.1",
'jshint-stylish': "^2.1.0",
mocha: "^2.4.5"
},
scripts: {
build: 'node ./lib/cli.js -c package.json5',
test: 'mocha --ui exports --reporter spec',
// TODO: Would it be better to define these in a mocha.opts file?
},
homepage: 'http://json5.org/',
license: 'MIT',
repository: {
type: 'git',
url: 'https://github.com/aseemk/json5.git',
},
}
```
## Community
Join the [Google Group](http://groups.google.com/group/json5) if youre
interested in JSON5 news, updates, and general discussion.
Dont worry, its very low-traffic.
The [GitHub wiki](https://github.com/aseemk/json5/wiki) is a good place to track
JSON5 support and usage. Contribute freely there!
[GitHub Issues](https://github.com/aseemk/json5/issues) is the place to
formally propose feature requests and report bugs. Questions and general
feedback are better directed at the Google Group.
## Usage
This JavaScript implementation of JSON5 simply provides a `JSON5` object just
like the native ES5 `JSON` object.
To use from Node:
```sh
npm install json5
```
```js
var JSON5 = require('json5');
```
To use in the browser (adds the `JSON5` object to the global namespace):
```html
<script src="json5.js"></script>
```
Then in both cases, you can simply replace native `JSON` calls with `JSON5`:
```js
var obj = JSON5.parse('{unquoted:"key",trailing:"comma",}');
var str = JSON5.stringify(obj);
```
`JSON5.parse` supports all of the JSON5 features listed above (*TODO: except
Unicode*), as well as the native [`reviver` argument][json-parse].
[json-parse]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse
`JSON5.stringify` mainly avoids quoting keys where possible, but we hope to
keep expanding it in the future (e.g. to also output trailing commas).
It supports the native [`replacer` and `space` arguments][json-stringify],
as well. *(TODO: Any implemented `toJSON` methods arent used today.)*
[json-stringify]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
### Extras
If youre running this on Node, you can also register a JSON5 `require()` hook
to let you `require()` `.json5` files just like you can `.json` files:
```js
require('json5/lib/require');
require('./path/to/foo'); // tries foo.json5 after foo.js, foo.json, etc.
require('./path/to/bar.json5');
```
This module also provides a `json5` executable (requires Node) for converting
JSON5 files to JSON:
```sh
json5 -c path/to/foo.json5 # generates path/to/foo.json
```
## Development
```sh
git clone git://github.com/aseemk/json5.git
cd json5
npm install
npm test
```
As the `package.json5` file states, be sure to run `npm run build` on changes
to `package.json5`, since npm requires `package.json`.
Feel free to [file issues](https://github.com/aseemk/json5/issues) and submit
[pull requests](https://github.com/aseemk/json5/pulls) — contributions are
welcome. If you do submit a pull request, please be sure to add or update the
tests, and ensure that `npm test` continues to pass.
## License
MIT. See [LICENSE.md](./LICENSE.md) for details.
## Credits
[Michael Bolin](http://bolinfest.com/) independently arrived at and published
some of these same ideas with awesome explanations and detail.
Recommended reading:
[Suggested Improvements to JSON](http://bolinfest.com/essays/json.html)
[Douglas Crockford](http://www.crockford.com/) of course designed and built
JSON, but his state machine diagrams on the [JSON website](http://json.org/),
as cheesy as it may sound, gave me motivation and confidence that building a
new parser to implement these ideas this was within my reach!
This code is also modeled directly off of Dougs open-source [json_parse.js][]
parser. Im super grateful for that clean and well-documented code.
[json_parse.js]: https://github.com/douglascrockford/JSON-js/blob/master/json_parse.js
[Max Nanasy](https://github.com/MaxNanasy) has been an early and prolific
supporter, contributing multiple patches and ideas. Thanks Max!
[Andrew Eisenberg](https://github.com/aeisenberg) has contributed the
`stringify` method.
[Jordan Tucker](https://github.com/jordanbtucker) has aligned JSON5 more closely
with ES5 and is actively maintaining this project.