jiff/lib/jsonPointerParse.js

JSON diff and patch based on rfc6902

/** @license MIT License (c) copyright 2010-2014 original author or authors */
/** @author Brian Cavalier */
/** @author John Hann */

module.exports = jsonPointerParse;

var parseRx = /\/|~1|~0/g;
var separator = '/';
var escapeChar = '~';
var encodedSeparator = '~1';

/**
 * Parse through an encoded JSON Pointer string, decoding each path segment
 * and passing it to an onSegment callback function.
 * @see https://tools.ietf.org/html/rfc6901#section-4
 * @param {string} path encoded JSON Pointer string
 * @param {{function(segment:string):boolean}} onSegment callback function
 * @returns {string} original path
 */
function jsonPointerParse(path, onSegment) {
	var pos, accum, matches, match;

	pos = path.charAt(0) === separator ? 1 : 0;
	accum = '';
	parseRx.lastIndex = pos;

	while(matches = parseRx.exec(path)) {

		match = matches[0];
		accum += path.slice(pos, parseRx.lastIndex - match.length);
		pos = parseRx.lastIndex;

		if(match === separator) {
			if (onSegment(accum) === false) return path;
			accum = '';
		} else {
			accum += match === encodedSeparator ? separator : escapeChar;
		}
	}

	accum += path.slice(pos);
	onSegment(accum);

	return path;
}