250 lines
6.4 KiB
Markdown
250 lines
6.4 KiB
Markdown
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JS-YAML - YAML 1.2 parser and serializer for JavaScript
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=======================================================
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[](http://travis-ci.org/nodeca/js-yaml)
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[Online Demo](http://nodeca.github.com/js-yaml/)
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This is an implementation of [YAML](http://yaml.org/), a human friendly data
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serialization language. Started as [PyYAML](http://pyyaml.org/) port, it was
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completely rewritten from scratch. Now it's very fast, and supports 1.2 spec.
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Breaking changes in 1.x.x -> 2.0.x
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----------------------------------
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If your have not used __custom__ tags or loader classes - no changes needed. Just
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upgrade library and enjoy high parse speed.
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In other case, you should rewrite your tag constructors and custom loader
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classes, to conform new schema-based API. See
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[examples](https://github.com/nodeca/js-yaml/tree/master/examples) and
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[wiki](https://github.com/nodeca/js-yaml/wiki) for details.
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Note, that parser internals were completely rewritten.
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Installation
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------------
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### YAML module for node.js
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```
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npm install js-yaml
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```
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### CLI executable
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If you want to inspect your YAML files from CLI, install js-yaml globally:
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```
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npm install js-yaml -g
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```
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#### Usage
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```
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usage: js-yaml [-h] [-v] [-c] [-j] [-t] file
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Positional arguments:
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file File with YAML document(s)
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Optional arguments:
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-h, --help Show this help message and exit.
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-v, --version Show program's version number and exit.
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-c, --compact Display errors in compact mode
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-j, --to-json Output a non-funky boring JSON
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-t, --trace Show stack trace on error
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```
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### Bundled YAML library for browsers
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``` html
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<script src="js-yaml.min.js"></script>
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<script type="text/javascript">
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var doc = jsyaml.load('greeting: hello\nname: world');
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</script>
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```
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Browser support was done mostly for online demo. If you find any errors - feel
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free to send pull requests with fixes. Also note, that IE and other old browsers
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needs [es5-shims](https://github.com/kriskowal/es5-shim) to operate.
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API
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---
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Here we cover the most 'useful' methods. If you need advanced details (creating
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your own tags), see [wiki](https://github.com/nodeca/js-yaml/wiki) and
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[examples](https://github.com/nodeca/js-yaml/tree/master/examples) for more
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info.
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In node.js JS-YAML automatically registers handlers for `.yml` and `.yaml`
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files. You can load them just with `require`. That's mostly equivalent to
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calling `load()` on fetched content of a file. Just with one string!
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``` javascript
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require('js-yaml');
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// Get document, or throw exception on error
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try {
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var doc = require('/home/ixti/example.yml');
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console.log(doc);
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} catch (e) {
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console.log(e);
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}
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```
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### load (string [ , options ])
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Parses `string` as single YAML document. Returns a JavaScript object or throws
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`YAMLException` on error.
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NOTE: This function **does not** understands multi-document sources, it throws
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exception on those.
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options:
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- `filename` _(default: null)_ - string to be used as a file path in
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error/warning messages.
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- `strict` _(default - false)_ makes the loader to throw errors instead of
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warnings.
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- `schema` _(default: `DEFAULT_SCHEMA`)_ - specifies a schema to use.
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### loadAll (string, iterator [ , options ])
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Same as `load()`, but understands multi-document sources and apply `iterator` to
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each document.
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``` javascript
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var yaml = require('js-yaml');
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yaml.loadAll(data, function (doc) {
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console.log(doc);
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});
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```
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### safeLoad (string [ , options ])
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Same as `load()` but uses `SAFE_SCHEMA` by default - only recommended tags of
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YAML specification (no JavaScript-specific tags, e.g. `!!js/regexp`).
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### safeLoadAll (string, iterator [ , options ])
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Same as `loadAll()` but uses `SAFE_SCHEMA` by default - only recommended tags of
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YAML specification (no JavaScript-specific tags, e.g. `!!js/regexp`).
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### dump (object [ , options ])
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Serializes `object` as YAML document.
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options:
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- `indent` _(default: 2)_ - indentation width to use (in spaces).
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- `flowLevel` (default: -1) - specifies level of nesting, when to switch from
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block to flow style for collections. -1 means block style everwhere
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- `styles` - "tag" => "style" map. Each tag may have own set of styles.
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- `schema` _(default: `DEFAULT_SCHEMA`)_ specifies a schema to use.
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styles:
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``` none
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!!null
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"canonical" => "~"
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!!int
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"binary" => "0b1", "0b101010", "0b1110001111010"
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"octal" => "01", "052", "016172"
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"decimal" => "1", "42", "7290"
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"hexadecimal" => "0x1", "0x2A", "0x1C7A"
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!!null, !!bool, !!float
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"lowercase" => "null", "true", "false", ".nan", '.inf'
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"uppercase" => "NULL", "TRUE", "FALSE", ".NAN", '.INF'
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"camelcase" => "Null", "True", "False", ".NaN", '.Inf'
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```
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By default, !!int uses `decimal`, and !!null, !!bool, !!float use `lowercase`.
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### safeDump (object [ , options ])
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Same as `dump()` but uses `SAFE_SCHEMA` by default - only recommended tags of
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YAML specification (no JavaScript-specific tags, e.g. `!!js/regexp`).
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Supported YAML types
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--------------------
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The list of standard YAML tags and corresponding JavaScipt types. See also
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[YAML tag discussion](http://pyyaml.org/wiki/YAMLTagDiscussion) and
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[YAML types repository](http://yaml.org/type/).
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```
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!!null '' # null
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!!bool 'yes' # bool
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!!int '3...' # number
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!!float '3.14...' # number
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!!binary '...base64...' # buffer
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!!timestamp 'YYYY-...' # date
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!!omap [ ... ] # array of key-value pairs
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!!pairs [ ... ] # array or array pairs
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!!set { ... } # array of objects with given keys and null values
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!!str '...' # string
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!!seq [ ... ] # array
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!!map { ... } # object
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```
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**JavaScript-specific tags**
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```
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!!js/regexp /pattern/gim # RegExp
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!!js/undefined '' # Undefined
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!!js/function 'function () {...}' # Function
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```
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## Caveats
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Note, that you use arrays or objects as key in JS-YAML. JS do not allows objects
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or array as keys, and stringifies (by calling .toString method) them at the
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moment of adding them.
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``` yaml
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---
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? [ foo, bar ]
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: - baz
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? { foo: bar }
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: - baz
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- baz
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```
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``` javascript
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{ "foo,bar": ["baz"], "[object Object]": ["baz", "baz"] }
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```
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Also, reading of properties on implicit block mapping keys is not supported yet.
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So, the following YAML document cannot be loaded.
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``` yaml
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&anchor foo:
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foo: bar
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*anchor: duplicate key
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baz: bat
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*anchor: duplicate key
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```
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## License
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View the [LICENSE](https://github.com/nodeca/js-yaml/blob/master/LICENSE) file
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(MIT).
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