yaml-types
v0.3.0
Published
Useful JavaScript types for YAML
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yaml-types
Additional useful types for yaml
.
Installation and Usage
npm install yaml yaml-types
Each type (a.k.a. "tag") is available as a named export of 'yaml-types'
.
These may then be used as custom tags:
import { parse } from 'yaml'
import { regexp } from 'yaml-types'
const re = parse('!re /fo./g', { customTags: [regexp] })
'foxbarfoo'.match(re) // [ 'fox', 'foo' ]
Available Types
bigint
(!bigint
) - JavaScript BigInt values. Note: in order to use this effectively, a function must be provided ascustomTags
in order to prepend thebigint
tag, or else the built-in!!int
tags will take priority. See bigint.test.ts for examples.classTag
(!class
) - JavaScript Class valueserror
(!error
) - JavaScript Error objectsfunctionTag
(!function
) - JavaScript Function values (will also be used to stringify Class values, unless theclassTag
tag is loaded ahead offunctionTag
)nullobject
(!nullobject) - Object with a
null` prototyperegexp
(!re
) - RegExp values, using their default/foo/flags
string representation.sharedSymbol
(!symbol/shared
) - Shared Symbols, i.e. ones created withSymbol.for()
symbol
(!symbol
) - Unique Symbols
The function and class values created by parsing !function
and
!class
tags will not actually replicate running code, but
rather no-op function/class values with matching name and
toString
properties.
Customising Tag Names
To use one of the types with a different tag identifier, set its tag
value accordingly.
For example, to extend the default tag namespace with !!js/regexp
instead of using a local !re
tag for RegExp values:
import { stringify } from 'yaml'
import { regexp } from 'yaml-types'
const myregexp = { ...regexp, tag: 'tag:yaml.org,2002:js/regexp' }
stringify(/fo./m, { customTags: [myregexp] })
!!js/regexp /fo./m
To use a named tag handle like !js!regexp
, a few more steps are required:
import { Document } from 'yaml'
import { regexp } from 'yaml-types'
const myregexp = { ...regexp, tag: 'tag:js:regexp' }
const doc = new Document(/fo./m, { customTags: [myregexp] })
doc.directives.tags['!js!'] = 'tag:js:'
doc.toString()
%TAG !js! tag:js:
---
!js!regexp /fo./m
Contributing
Additions to this library are very welcome!
Many data types are useful beyond any single project,
and while the core yaml
library is mostly limited to the YAML spec,
no such restriction applies here.
The source code is written in TypeScript, and the tests use Node-Tap. When submitting a PR for a new type, tests and documentation are required, as well as satisfying Prettier.