feat(regex): Add support for pluggable regex engines for use in evaluation (#491)

Author: maxwellgerber

src/jsonata.js

@@ -1088,7 +1088,7 @@ var jsonata = (function() {
      * @returns {Function} Higher order function representing prepared regex
      */
     function evaluateRegex(expr) {
-        var re = new RegExp(expr.value);
+        var re = new jsonata.RegexEngine(expr.value);
         var closure = function(str, fromIndex) {
             var result;
             re.lastIndex = fromIndex || 0;
@@ -2041,7 +2041,9 @@ var jsonata = (function() {
     /**
      * JSONata
      * @param {Object} expr - JSONata expression
-     * @param {boolean} options - recover: attempt to recover on parse error
+     * @param {Object} options
+     * @param {boolean} options.recover: attempt to recover on parse error
+     * @param {Function} options.RegexEngine: RegEx class constructor to use
      * @returns {{evaluate: evaluate, assign: assign}} Evaluated expression
      */
     function jsonata(expr, options) {
@@ -2066,6 +2068,12 @@ var jsonata = (function() {
             return timestamp.getTime();
         }, '<:n>'));
 
+        if(options && options.RegexEngine) {
+            jsonata.RegexEngine = options.RegexEngine;
+        } else {
+            jsonata.RegexEngine = RegExp;
+        }
+
         return {
             evaluate: function (input, bindings, callback) {
                 // throw if the expression compiled with syntax errors

test/parser-pluggable-regex.js

@@ -0,0 +1,28 @@
+"use strict";
+
+var jsonata = require('../src/jsonata');
+var assert = require('assert');
+var chai = require("chai");
+var expect = chai.expect;
+
+describe('Invoke parser with custom RegexEngine param', function() {
+
+    var regexContentSpy = null;
+    var regexEvalSpy = null;
+
+    function RegexEngineSpy(content) {
+        regexContentSpy = content;
+
+        this.exec = function(input) {
+            regexEvalSpy = input;
+            return null;
+        }
+    }
+
+    it('should call RegexEngine param constructure during evaluation', function() {
+        var expr = jsonata('$replace(\"foo\", /bar/, \"baaz\")', { RegexEngine: RegexEngineSpy });
+        expr.evaluate()
+        assert.deepEqual(regexContentSpy.toString(), "/bar/g");
+        assert.deepEqual(regexEvalSpy, "foo");
+    });
+});