Path Parser

@finnair/path-parser contains nearley.js based parsers for Path and PathMatcher.

See @finnair/path or instructions on how to use Path and PathMatcher.

Getting Started

Install v-validation using yarn:

yarn add @finnair/path-parser

Or npm:

npm install @finnair/path-parser

Parsing Paths

import { parsePath } from '@finnair/path-parser';

parsePath(`$.array[1]["\\"property\\" with spaces and 'quotes'"]`); // JSON string encoded in brackets!
// Path.of('array', 1, `"property" with spaces and 'quotes'`);

// Single quotes also work, but encoding is still JSON string so the value cannot contain ' character
parsePath(`$['single quotes']`); // Path.of('single quotes')
parsePath(`$['single\'quote']`); // Fail!

// ...without using unicode escape
parsePath(`$['\\u0027']`); // Path.of("'");

Parsing PathMatchers

parsePathMatcher parses simple JsonPath like expressions. Supported expressions are

| Expression | Description  | | ----------------------------------- | --------------------------------------------------------------------- | | $.property | Identifiers matching RegExp /^[a-zA-Z_][a-zA-Z0-9_]*$/ | | $[0] | Index match | | $.* | Any property matcher, wildcard (matches also array indexes) | | $[*] | Any index matcher, wildcard (matches only array indexes) | | $["JSON string encoded property"] | Property as JSON encoded string | | $['JSON string encoded property'] | Property as single quoted, but otherwise JSON encoded, string(*) | | $[union,"of",4,'components'] | Union matcher that also supports identifiers and JSON encoded strings |

*) This is the official way of JsonPath, but the specification is a bit unclear on the encoding. In this library we prefer proper JSON string encoding with double quotes.

import { parsePathMatcher } from '@finnair/path-parser';

parsePathMatcher(`$.array[0][*].*['union',"of",properties,1]`);
// PathMatcher.of(
//   'array',
//    0,
//   AnyIndex,
//   AnyProperty,
//   UnionMatcher.of('union', 'of', 'properties', 1)
// )