A PEG.js parser for ICU MessageFormat strings – part of messageformat.js. Outputs an AST defined by parser.pegjs.
The generated parser function takes two parameters, first the string to be parsed, and a second optional parameter options, an object with the following possible keys:
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cardinalandordinal– Arrays of valid plural categories for the current locale, used to validate plural and selectordinal keys. If these are missing or set to false, the full set of valid Unicode CLDR keys is used:'zero', 'one', 'two', 'few', 'many', 'other'. To disable this check, pass in an empty array. -
strictFunctionParams– By default, function parameters are split on commas and trimmed, so the parameters in{x,fn, a, b }are parsed as['a','b']. SettingstrictFunctionParamsto true will make the parser follow the ICU MessageFormat spec more closely, and result in a params array with a single element:[' a, b '].
npm install messageformat-parser> var parse = require('messageformat-parser').parse; > parse('So {wow}.') [ 'So ', { type: 'argument', arg: 'wow' }, '.' ] > parse('Such { thing }. { count, selectordinal, one {First} two {Second}' + ' few {Third} other {#th} } word.') [ 'Such ', { type: 'argument', arg: 'thing' }, '. ', { type: 'selectordinal', arg: 'count', offset: 0, cases: [ { key: 'one', tokens: [ 'First' ] }, { key: 'two', tokens: [ 'Second' ] }, { key: 'few', tokens: [ 'Third' ] }, { key: 'other', tokens: [ { type: 'octothorpe' }, 'th' ] } ] }, ' word.' ] > parse('Many{type,select,plural{ numbers}selectordinal{ counting}' + 'select{ choices}other{ some {type}}}.') [ 'Many', { type: 'select', arg: 'type', cases: [ { key: 'plural', tokens: [ ' numbers' ] }, { key: 'selectordinal', tokens: [ ' counting' ] }, { key: 'select', tokens: [ ' choices' ] }, { key: 'other', tokens: [ ' some', { type: 'argument', arg: 'type' } ] } ] }, '.' ] > parse('{Such compliance') // SyntaxError: Expected ",", "}" or [ \t\n\r] but "c" found. > var msg = '{words, plural, zero{No words} one{One word} other{# words}}'; > var englishKeys = { cardinal: [ 'one', 'other' ], ordinal: [ 'one', 'two', 'few', 'other' ] }; > parse(msg) [ { type: 'plural', arg: 'words', offset: 0, cases: [ { key: 'zero', tokens: [ 'No words' ] }, { key: 'one', tokens: [ 'One word' ] }, { key: 'other', tokens: [ { type: 'octothorpe' }, ' words' ] } ] } ] > parse(msg, englishKeys) // Error: Invalid key `zero` for argument `words`. Valid plural keys for this // locale are `one`, `other`, and explicit keys like `=0`.See the messageformat.js README for details.