parser package

An AST parser for ICU MessageFormat strings

Example

import { parse } from '@messageformat/parser

parse('So {wow}.')
[ { type: 'content', value: 'So ' },
  { type: 'argument', arg: 'wow' },
  { type: 'content', value: '.' } ]


parse('Such { thing }. { count, selectordinal, one {First} two {Second}' +
      '                  few {Third} other {#th} } word.')
[ { type: 'content', value: 'Such ' },
  { type: 'argument', arg: 'thing' },
  { type: 'content', value: '. ' },
  { type: 'selectordinal',
    arg: 'count',
    cases: [
      { key: 'one', tokens: [ { type: 'content', value: 'First' } ] },
      { key: 'two', tokens: [ { type: 'content', value: 'Second' } ] },
      { key: 'few', tokens: [ { type: 'content', value: 'Third' } ] },
      { key: 'other',
        tokens: [ { type: 'octothorpe' }, { type: 'content', value: 'th' } ] }
    ] },
  { type: 'content', value: ' word.' } ]


parse('Many{type,select,plural{ numbers}selectordinal{ counting}' +
                         'select{ choices}other{ some {type}}}.')
[ { type: 'content', value: 'Many' },
  { type: 'select',
    arg: 'type',
    cases: [
      { key: 'plural', tokens: [ { type: 'content', value: 'numbers' } ] },
      { key: 'selectordinal', tokens: [ { type: 'content', value: 'counting' } ] },
      { key: 'select', tokens: [ { type: 'content', value: 'choices' } ] },
      { key: 'other',
        tokens: [ { type: 'content', value: 'some ' }, { type: 'argument', arg: 'type' } ] }
    ] },
  { type: 'content', value: '.' } ]


parse('{Such compliance')
// ParseError: invalid syntax at line 1 col 7:
//
//  {Such compliance
//        ^


const msg = '{words, plural, zero{No words} one{One word} other{# words}}'
parse(msg)
[ { type: 'plural',
    arg: 'words',
    cases: [
      { key: 'zero', tokens: [ { type: 'content', value: 'No words' } ] },
      { key: 'one', tokens: [ { type: 'content', value: 'One word' } ] },
      { key: 'other',
        tokens: [ { type: 'octothorpe' }, { type: 'content', value: ' words' } ] }
    ] } ]


parse(msg, { cardinal: [ 'one', 'other' ], ordinal: [ 'one', 'two', 'few', 'other' ] })
// ParseError: The plural case zero is not valid in this locale at line 1 col 17:
//
//   {words, plural, zero{
//                   ^

Classes

Class	Description
ParseError	Thrown by parse() on error

Functions

Function	Description
parse(src, options)	Parse an input string into an array of tokens

Interfaces

Interface	Description
Content	Text content of the message
Context	The parsing context for a token
FunctionArg	A placeholder for a mapped argument
Octothorpe	Represents the # character
ParseOptions	Options for the parser
PlainArg	A simple placeholder
Select	A selector between multiple variants
SelectCase	A case within a Select

Type Aliases

Type Alias	Description
PluralCategory	One of the valid Unicode CLDR plural category keys