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