What?

Transform fancy string values to usable JS objects.
Helpful for parsing HTML attribute values in custom elements/web components.

import parseOption from 'fancy-value-parser'

parseOption('foo')       // { type: null, value: 'foo' }
parseOption('foo:666')   // { type: 'pair', foo: 666, value: [{⋯}, {⋯}] }
parseOption('0-42')      // { type: 'range', value: [0, 42] }
parseOption('true')      // { type: 'boolean', value: true }
parseOption('/foo/')     // { type: 'regex', value: /foo/ }
parseOption('{foo,bar}') // { type: 'set', value: [{⋯}, {⋯}] }

In / Out

| in (as a string) | out (structured JS) | | -- | --- | | foobar | { type: null, value: 'foobar' } | | 'foobar' | { type: 'string', value: 'foobar' } | | /regex/ | { type: 'regex', value: /regex/ } | | 303 | { type: 'number', value: 303 } | | 3-5 | { type: 'range', value: [3, 5] } | | true | { type: 'boolean', value: true } | | foo:bar | { type: 'pair', foo: 'bar', value: [{⋯}, {⋯}] } | | {1, /no[pe]/, foo:bar} | { type: 'set', value: [{⋯}, {⋯}, {⋯}] } |

Notes

• Various types can be combined with simple pairs and sets.
• Pairs are read left-to-right.
• Sets cannot contain other sets.

Not yet supported

• ~~key-value pairs like foo:bar~~
• ~~booleans~~
• dates
• floating point numbers

~~I'm hesitant to support more complex types; at that point, the state being conveyed shouldn't be transported as strings.~~
Clearly this ☝️ goal has been abandoned with the addition of pairs and sets. But there are good use cases and they are well tested.