js-yaml
Advanced tools
Package description
The js-yaml npm package is a JavaScript library that allows you to parse and dump YAML, a human-friendly data serialization standard. It can be used to convert YAML to JSON and vice versa, making it a useful tool for configuration files, data exchange, and more.
YAML Parsing
This feature allows you to parse a YAML file or string and convert it into a JavaScript object. The code sample demonstrates how to read a YAML file from the filesystem and parse its contents.
{"const yaml = require('js-yaml');\nconst fs = require('fs');\n\ntry {\n const doc = yaml.load(fs.readFileSync('/path/to/file.yml', 'utf8'));\n console.log(doc);\n} catch (e) {\n console.error(e);\n}"}YAML Dumping
This feature allows you to take a JavaScript object and convert it into a YAML-formatted string. The code sample shows how to create a YAML string from an object and then save it to a file.
{"const yaml = require('js-yaml');\nconst fs = require('fs');\n\nconst obj = { hello: 'world' };\nconst ymlText = yaml.dump(obj);\n\nfs.writeFileSync('/path/to/file.yml', ymlText, 'utf8');\nconsole.log('YAML file saved.');"}Custom Types
js-yaml allows you to define custom types for specialized use cases. The code sample demonstrates how to create a custom YAML type and use it in parsing a YAML string.
{"const yaml = require('js-yaml');\n\nconst schema = yaml.Schema.create([ new yaml.Type('!myType', {\n kind: 'scalar',\n resolve: data => data === 'valid',\n construct: data => data,\n instanceOf: String\n}) ]);\n\nconst doc = yaml.load('!myType valid', { schema });\nconsole.log(doc); // 'valid'"}The 'yaml' package is another JavaScript library for parsing and serializing YAML. It offers a similar API to js-yaml but with a focus on being highly compliant with the YAML specification. It may be preferred for applications that require strict adherence to the spec.
Yamljs is a JavaScript library that provides YAML parsing and dumping functionalities. It is similar to js-yaml but has a different API design and may not be as actively maintained as js-yaml.
This package is designed for parsing YAML into an abstract syntax tree (AST). It is useful for developers who need to analyze or manipulate the structure of YAML documents at a lower level compared to js-yaml.
Changelog
[0.2.0] - 2011-11-02
Readme
YAML 1.1 parser for JavaScript. Originally ported from PyYAML.
(*) Not feature-compleete, more coming soon:
For node.js:
npm install js-yaml
JS-YAML automatically registers handlers for .yml and .yaml files. You can load them just with require.
That's equivalent to calling loadAll() on file handler. Just with one string!
require('js-yaml');
// Get array of documents, or throw exception on error
var docs = require('/home/ixti/examples.yml');
console.log(docs);
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);
}
});
The same as Load, but understands multi-doc sources and returns array of JS objects.
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.loadAll(data) );
} catch(e) {
console.log(e);
}
});
The list of standard YAML tags and corresponding JavaScipt types. See also YAMLTagDiscussion 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
The list of JS-specific YAML tags will be availble soon (not implemented yet) and will probably include RegExp, Undefined, function and Infinity.
View the LICENSE file
FAQs
YAML 1.2 parser and serializer
We found that js-yaml demonstrated a not healthy version release cadence and project activity because the last version was released a year ago. It has 1 open source maintainer collaborating on the project.
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