JS-YAML - YAML 1.1 parser for JavaScript

Online Demo

This is a native port of PyYAML, the most advanced YAML parser. Now you can use all modern YAML feature right in JavaScript. Originally snapshoted version - PyYAML 3.10 (2011-05-30).

Breaking changes in 0.3.x -> 1.0.x

• y, yes, n, no, on, off are not converted to Booleans anymore. Decision to drop support of such "magic" was made after speaking with YAML core developers: from now on we try to keep as minimal subset of rules as possible to keep things obvious. Booleans are following YAML 1.2 core schema now: http://www.yaml.org/spec/1.2/spec.html#id2804923
• require('file.yml') now returns a single document (was array of documents) and throws an error when file contains multiple documents. That should improve switching between YAML <-> JSON. require('file.json') will give the same result now.
• js-yaml.bin become part of js-yaml again.

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 browser

<script src="js-yaml.min.js"></script>
<script type="text/javascript">
var doc = jsyaml.load('greeting: hello\nname: world');
</script>

Browser support is still buggy, and mostly done to run online demo. If you can help to improve browser compatibility and AMD support - rise pull request.

Support of oldIEs and some other prehistoric browsers is possible using es5-shims. Just include shims before jsyaml to use it with outdated browsers.

API

JS-YAML automatically registers handlers for .yml and .yaml files. You can load them just with require. That's mostly equivalent to calling loadAll() on file handler ang gathering all documents into array. Just with one string!

require('js-yaml');

// Get document, or throw exception on error
var doc = require('/home/ixti/example.yml');

console.log(doc);

load (string|buffer|file_resource)

Parses source as single YAML document. Returns JS object or throws exception on error.

This function does NOT understands multi-doc sources, it throws exception on those.

var yaml = require('js-yaml');

// pass the string
fs.readFile('/home/ixti/example.yml', 'utf8', function (err, data) {
  if (err) {
    // handle error
    return;
  }
  try {
    console.log( yaml.load(data) );
  } catch(e) {
    console.log(e);
  }
});

loadAll (string|buffer|file_resource, iterator)

Same as Load, but understands multi-doc sources and apply iterator to each document.

var yaml = require('js-yaml');

// pass the string
fs.readFile('/home/ixti/example.yml', 'utf8', function (err, data) {
  if (err) {
    // handle error
    return;
  }

  try {
    yaml.loadAll(data, function (doc) {
      console.log(doc);
    });
  } catch(e) {
    console.log(e);
  }
});

safeLoad (string|buffer|file_resource)

Same as load() but uses safe schema - only recommended tags of YAML specification (no JavaScript-specific tags, e.g. !!js/regexp).

safeLoadAll (string|buffer|file_resource, iterator)

Same as loadAll() but uses safe schema - only recommended tags of YAML specification (no JavaScript-specific tags, e.g. !!js/regexp).

JavaScript YAML tags scheme

The list of standard YAML tags and corresponding JavaScipt types. See also YAML Tag Discussion and Yaml Types.

!!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 them at the moment of adding them.

---
? [ foo, bar ]
: - baz
? { foo: bar }
: - baz
  - baz

=>

{ "": ["baz"], "[object Object]": ["baz", "baz"] }

License

View the LICENSE file (MIT).