Memoize results of parsing, normalization, and stringification, per dchester#75 (#1)

Author: jlutzhbo

lib/index.js

@@ -2,13 +2,15 @@ var assert = require('assert');
 var dict = require('./dict');
 var Parser = require('./parser');
 var Handlers = require('./handlers');
+var _ = require('underscore');
 
 var JSONPath = function() {
   this.initialize.apply(this, arguments);
 };
 
 JSONPath.prototype.initialize = function() {
   this.parser = new Parser();
+  this.parser.parse = _.memoize(this.parser.parse);
   this.handlers = new Handlers();
 };
 
@@ -152,7 +154,7 @@ JSONPath.prototype.nodes = function(obj, string, count) {
   return count ? matches.slice(0, count) : matches;
 };
 
-JSONPath.prototype.stringify = function(path) {
+JSONPath.prototype.stringify = _.memoize(function(path) {
 
   assert.ok(path, "we need a path");
 
@@ -187,9 +189,9 @@ JSONPath.prototype.stringify = function(path) {
   });
 
   return string;
-}
+});
 
-JSONPath.prototype._normalize = function(path) {
+JSONPath.prototype._normalize = _.memoize(function(path) {
 
   assert.ok(path, "we need a path");
 
@@ -234,7 +236,7 @@ JSONPath.prototype._normalize = function(path) {
   }
 
   throw new Error("couldn't understand path " + path);
-}
+});
 
 function _is_string(obj) {
   return Object.prototype.toString.call(obj) == '[object String]';