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https://github.com/dworthen/js-yaml-front-matter
Parses yaml or json from the beginning of a string or file
https://github.com/dworthen/js-yaml-front-matter
js-yaml json yaml yaml-frontmatter
Last synced: 6 days ago
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Parses yaml or json from the beginning of a string or file
- Host: GitHub
- URL: https://github.com/dworthen/js-yaml-front-matter
- Owner: dworthen
- License: mit
- Created: 2014-03-19T01:37:38.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2023-01-06T17:15:27.000Z (almost 2 years ago)
- Last Synced: 2024-09-08T06:14:05.617Z (2 months ago)
- Topics: js-yaml, json, yaml, yaml-frontmatter
- Language: JavaScript
- Homepage: https://dworthen.github.io/js-yaml-front-matter/
- Size: 1.49 MB
- Stars: 192
- Watchers: 4
- Forks: 17
- Open Issues: 20
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.md
Awesome Lists containing this project
README
# Yaml Front Matter
Parses yaml or json at the front of a string. Places the parsed content, plus the rest of the string content, into an object literal.
[Online Demo](https://dworthen.github.io/js-yaml-front-matter/).
#### Breaking Changes
This readme is for the 4.x release, which introduces breaking changes. View the [changelog](CHANGELOG.md) for more information.
[3.x readme](https://github.com/dworthen/js-yaml-front-matter/tree/v3.4.0)
## Example
This
```yaml
---
name: Derek Worthen
age: 127
contact:
email: [email protected]
address: some location
pets:
- cat
- dog
- bat
match: !!js/regexp /pattern/gim
run: !!js/function function() { }
---
Some Other content
```
```js
var fs = require('fs');
var yamlFront = require('yaml-front-matter');
fs.readFile('./some/file.txt', 'utf8', function(fileContents) {
console.log(yamlFront.loadFront(fileContents));
});
```
outputs
```js
{
name: 'Derek Worthen',
age: 127,
contact: { email: '[email protected]', address: 'some location' },
pets: [ 'cat', 'dog', 'bat' ],
match: /pattern/gim,
run: [Function],
__content: '\nSome Other Content'
}
```
May also use JSON
```json
---
{
"name": "Derek Worthen",
"age": "young",
"anArray": ["one","two"],
"subObj":{"field1": "one"}
}
---
Some content
```
> __NOTE:__ The `---` are required to denote the start and end of front matter. There must be a newline after the opening `---` and a newline preceding the closing `---`.
## Install
### npm
```shell
$ npm install yaml-front-matter
```
Use the `-g` flag if you plan on using the command line tool.
```shell
$ npm install yaml-front-matter -g
```
### Node or client with module bundler (webpack or browsify)
```js
var yamlFront = require('yaml-front-matter');
```
### Browser Bundle
The [dist/yamlFront.js](dist/yamlFront.js) client script will expose the yaml-front-matter library as a global, `yamlFront`. The client script for [js-yaml](https://github.com/nodeca/js-yaml) is also required. May need to load espirma for some use cases. See [js-yaml](https://github.com/nodeca/js-yaml) for more information.
```html
// parse front matter with yamlFront.loadFront(String);
```
> **Note**: yaml-front-matter is delivered as a umd package so it should work within commonjs, amd and browser (as a global) environments.
## Running Browser Example
```shell
$ npm install --dev && npm start
```
Then visit `localhost:8080`.
## Building from source
Outputs build files to `dist/`.
```shell
$ npm install --dev && npm run build
```
## Running Tests
```shell
npm install --dev && npm test
```
## Command Line
```shell
Usage: yaml-front-matter [options]
Options:
-h, --help output usage information
-v, --version output the version number
-c, --content [name] set the property name for the files contents [__content]
--pretty formats json output with spaces.
```
> **Note** The cli uses `safeLoadFront` and therefore will not parse yaml containing regexps, functions or undefined values.
### Example
```shell
# Piping content from one file, through yaml parser and into another file
cat ./some/file.txt | yaml-front-matter > output.txt
```
## JS-YAML
Yaml front matter wraps [js-yaml](https://github.com/nodeca/js-yaml) to support parsing yaml front-matter.
## API
### loadFront(string, [options])
```js
var input = [
'---\npost: title one\n',
'anArray:\n - one\n - two\n',
'subObject:\n prop1: cool\n prop2: two',
'\nreg: !!js/regexp /pattern/gim',
'\nfun: !!js/function function() { }\n---\n',
'content\nmore'
].join('');
var results = yamlFront.loadFront(input);
console.log(results);
```
outputs
```shell
{ post: 'title one',
anArray: [ 'one', 'two' ],
subObject: { obj1: 'cool', obj2: 'two' },
reg: /pattern/gim,
fun: [Function],
__content: '\ncontent\nmore' }
```
Front-matter is optional.
```js
yamlFront.loadFront('Hello World');
// => { __content: "Hello World!" }
```
Content is optional
```js
yamlFront.loadFront('');
// => { __content: '' }
```
### safeLoadFront(string, [options])
Same api as loadFront except it does not support regexps, functions or undefined. See [js-yaml](https://github.com/nodeca/js-yaml) for more information.
### Options
The options object supports the same options available to [js-yaml](https://github.com/nodeca/js-yaml) and adds support for an additional key.
- `options.contentKeyName`: Specify the object key where to store content not parsed by yaml-front-matter. defaults to `__content`.
```js
yamlFront.loadFront('Hello World', {
contentKeyName: 'fileContents'
});
// => { fileContents: "Hello World" }
```