observable-slim.js

/*
 * 	Observable Slim
 *	Version 0.1.6
 * 	https://github.com/elliotnb/observable-slim
 *
 * 	Licensed under the MIT license:
 * 	http://www.opensource.org/licenses/MIT
 *
 *	Observable Slim is a singleton that allows you to observe changes made to an object and any nested
 *	children of that object. It is intended to assist with one-way data binding, that is, in MVC parlance,
 *	reflecting changes in the model to the view. Observable Slim aspires to be as lightweight and easily
 *	understood as possible. Minifies down to roughly 3000 characters.
 */
var ObservableSlim = (function() {
	var paths = [];
	// An array that stores all of the observables created through the public create() method below.
	var observables = [];
	// An array of all the objects that we have assigned Proxies to
	var targets = [];

	// An array of arrays containing the Proxies created for each target object. targetsProxy is index-matched with
	// 'targets' -- together, the pair offer a Hash table where the key is not a string nor number, but the actual target object
	var targetsProxy = [];

	// this variable tracks duplicate proxies assigned to the same target.
	// the 'set' handler below will trigger the same change on all other Proxies tracking the same target.
	// however, in order to avoid an infinite loop of Proxies triggering and re-triggering one another, we use dupProxy
	// to track that a given Proxy was modified from the 'set' handler
	var dupProxy = null;

	var _getProperty = function(obj, path) {
		return path.split('.').reduce(function(prev, curr) {
			return prev ? prev[curr] : undefined
		}, obj || self)
	};

	/**
	 * Create a new ES6 `Proxy` whose changes we can observe through the `observe()` method.
	 * @param {object} target Plain object that we want to observe for changes.
	 * @param {boolean|number} domDelay If `true`, then the observed changes to `target` will be batched up on a 10ms delay (via `setTimeout()`).
	 * If `false`, then the `observer` function will be immediately invoked after each individual change made to `target`. It is helpful to set
	 * `domDelay` to `true` when your `observer` function makes DOM manipulations (fewer DOM redraws means better performance). If a number greater
	 * than zero, then it defines the DOM delay in milliseconds.
	 * @param {function(ObservableSlimChange[])} [observer] Function that will be invoked when a change is made to the proxy of `target`.
	 * When invoked, this function is passed a single argument: an array of `ObservableSlimChange` detailing each change that has been made.
	 * @param {object} originalObservable The original observable created by the user, exists for recursion purposes, allows one observable to observe
	 * change on any nested/child objects.
	 * @param {{target: object, property: string}[]} originalPath Array of objects, each object having the properties `target` and `property`:
	 * `target` is referring to the observed object itself and `property` referring to the name of that object in the nested structure.
	 * The path of the property in relation to the target on the original observable, exists for recursion purposes, allows one observable to observe
	 * change on any nested/child objects.
	 * @returns {ProxyConstructor} Proxy of the target object.
	 */
	var _create = function(target, domDelay, originalObservable, originalPath) {

		var observable = originalObservable || null;

		// record the nested path taken to access this object -- if there was no path then we provide the first empty entry
		var path = originalPath || [{"target":target,"property":""}];
		paths.push(path);

		// in order to accurately report the "previous value" of the "length" property on an Array
		// we must use a helper property because intercepting a length change is not always possible as of 8/13/2018 in
		// Chrome -- the new `length` value is already set by the time the `set` handler is invoked
		if (target instanceof Array) {
			if (!target.hasOwnProperty("__length"))
				Object.defineProperty(target, "__length", { enumerable: false, value: target.length, writable: true });
			else
				target.__length = target.length;
		}

		var changes = [];

		/**
		 * Returns a string of the nested path (in relation to the top-level observed object) of the property being modified or deleted.
		 * @param {object} target Plain object that we want to observe for changes.
		 * @param {string} property Property name.
		 * @param {boolean} [jsonPointer] Set to `true` if the string path should be formatted as a JSON pointer rather than with the dot notation
		 * (`false` as default).
		 * @returns {string} Nested path (e.g., `hello.testing.1.bar` or, if JSON pointer, `/hello/testing/1/bar`).
		 */
		var _getPath = function(target, property, jsonPointer) {

			var fullPath = "";
			var lastTarget = null;

			// loop over each item in the path and append it to full path
			for (var i = 0; i < path.length; i++) {

				// if the current object was a member of an array, it's possible that the array was at one point
				// mutated and would cause the position of the current object in that array to change. we perform an indexOf
				// lookup here to determine the current position of that object in the array before we add it to fullPath
				if (lastTarget instanceof Array && !isNaN(path[i].property)) {
					path[i].property = lastTarget.indexOf(path[i].target);
				}

				fullPath = fullPath + "." + path[i].property
				lastTarget = path[i].target;
			}

			// add the current property
			fullPath = fullPath + "." + property;

			// remove the beginning two dots -- ..foo.bar becomes foo.bar (the first item in the nested chain doesn't have a property name)
			fullPath = fullPath.substring(2);

			if (jsonPointer === true) fullPath = "/" + fullPath.replace(/\./g, "/");

			return fullPath;
		};

		var _notifyObservers = function(numChanges) {

			// if the observable is paused, then we don't want to execute any of the observer functions
			if (observable.paused === true) return;

			var domDelayIsNumber = typeof domDelay === 'number';

			// execute observer functions on a 10ms setTimeout, this prevents the observer functions from being executed
			// separately on every change -- this is necessary because the observer functions will often trigger UI updates
 			if (domDelayIsNumber || domDelay === true) {
				setTimeout(function() {
					if (numChanges === changes.length) {

						// we create a copy of changes before passing it to the observer functions because even if the observer function
						// throws an error, we still need to ensure that changes is reset to an empty array so that old changes don't persist
						var changesCopy = changes.slice(0);
						changes = [];

						// invoke any functions that are observing changes
						for (var i = 0; i < observable.observers.length; i++) observable.observers[i](changesCopy);

					}
				}, (domDelayIsNumber && domDelay > 0) ? domDelay : 10);
			} else {

				// we create a copy of changes before passing it to the observer functions because even if the observer function
				// throws an error, we still need to ensure that changes is reset to an empty array so that old changes don't persist
				var changesCopy = changes.slice(0);
				changes = [];

				// invoke any functions that are observing changes
				for (var i = 0; i < observable.observers.length; i++) observable.observers[i](changesCopy);

			}
		};

		var handler = {
			get: function(target, property) {

				// implement a simple check for whether or not the object is a proxy, this helps the .create() method avoid
				// creating Proxies of Proxies.
				if (property === "__getTarget") {
					return target;
				} else if (property === "__isProxy") {
					return true;
				// from the perspective of a given observable on a parent object, return the parent object of the given nested object
				} else if (property === "__getParent") {
					return function(i) {
						if (typeof i === "undefined") var i = 1;
						var parentPath = _getPath(target, "__getParent").split(".");
						parentPath.splice(-(i+1),(i+1));
						return _getProperty(observable.parentProxy, parentPath.join("."));
					}
				// return the full path of the current object relative to the parent observable
				} else if (property === "__getPath") {
					// strip off the 12 characters for ".__getParent"
					var parentPath = _getPath(target, "__getParent");
					return parentPath.slice(0, -12);
				}

				// for performance improvements, we assign this to a variable so we do not have to lookup the property value again
				var targetProp = target[property];
				if (target instanceof Date && targetProp instanceof Function && targetProp !== null) {
					return targetProp.bind(target);
				}

				// if we are traversing into a new object, then we want to record path to that object and return a new observable.
				// recursively returning a new observable allows us a single Observable.observe() to monitor all changes on
				// the target object and any objects nested within.
				if (targetProp instanceof Object && targetProp !== null && target.hasOwnProperty(property)) {

					// if we've found a proxy nested on the object, then we want to retrieve the original object behind that proxy
					if (targetProp.__isProxy === true) targetProp = targetProp.__getTarget;

					// if the object accessed by the user (targetProp) already has a __targetPosition AND the object
					// stored at target[targetProp.__targetPosition] is not null, then that means we are already observing this object
					// we might be able to return a proxy that we've already created for the object
					if (targetProp.__targetPosition > -1 && targets[targetProp.__targetPosition] !== null) {

						// loop over the proxies that we've created for this object
						var ttp = targetsProxy[targetProp.__targetPosition];
						for (var i = 0, l = ttp.length; i < l; i++) {

							// if we find a proxy that was setup for this particular observable, then return that proxy
							if (observable === ttp[i].observable) {
								return ttp[i].proxy;
							}
						}
					}

					// if we're arrived here, then that means there is no proxy for the object the user just accessed, so we
					// have to create a new proxy for it

					// create a shallow copy of the path array -- if we didn't create a shallow copy then all nested objects would share the same path array and the path wouldn't be accurate
					var newPath = path.slice(0);
					newPath.push({"target":targetProp,"property":property});
					return _create(targetProp, domDelay, observable, newPath);
				} else {
					return targetProp;
				}
			},
 			deleteProperty: function(target, property) {

				// was this change an original change or was it a change that was re-triggered below
				var originalChange = true;
				if (dupProxy === proxy) {
					originalChange = false;
					dupProxy = null;
				}

				// in order to report what the previous value was, we must make a copy of it before it is deleted
				var previousValue = Object.assign({}, target);

				// record the deletion that just took place
				changes.push({
					"type":"delete"
					,"target":target
					,"property":property
					,"newValue":null
					,"previousValue":previousValue[property]
					,"currentPath":_getPath(target, property)
					,"jsonPointer":_getPath(target, property, true)
					,"proxy":proxy
				});

				if (originalChange === true) {

					// perform the delete that we've trapped if changes are not paused for this observable
					if (!observable.changesPaused) delete target[property];

					for (var a = 0, l = targets.length; a < l; a++) if (target === targets[a]) break;

					// loop over each proxy and see if the target for this change has any other proxies
					var currentTargetProxy = targetsProxy[a] || [];

					var b = currentTargetProxy.length;
					while (b--) {
						// if the same target has a different proxy
						if (currentTargetProxy[b].proxy !== proxy) {
							// !!IMPORTANT!! store the proxy as a duplicate proxy (dupProxy) -- this will adjust the behavior above appropriately (that is,
							// prevent a change on dupProxy from re-triggering the same change on other proxies)
							dupProxy = currentTargetProxy[b].proxy;

							// make the same delete on the different proxy for the same target object. it is important that we make this change *after* we invoke the same change
							// on any other proxies so that the previousValue can show up correct for the other proxies
							delete currentTargetProxy[b].proxy[property];
						}
					}

				}

				_notifyObservers(changes.length);

				return true;

			},
			set: function(target, property, value, receiver) {

				// if the value we're assigning is an object, then we want to ensure
				// that we're assigning the original object, not the proxy, in order to avoid mixing
				// the actual targets and proxies -- creates issues with path logging if we don't do this
				if (value && value.__isProxy) value = value.__getTarget;

				// was this change an original change or was it a change that was re-triggered below
				var originalChange = true;
				if (dupProxy === proxy) {
					originalChange = false;
					dupProxy = null;
				}

				// improve performance by saving direct references to the property
				var targetProp = target[property];

				// Only record this change if:
				// 	1. the new value differs from the old one
				//	2. OR if this proxy was not the original proxy to receive the change
				// 	3. OR the modified target is an array and the modified property is "length" and our helper property __length indicates that the array length has changed
				//
				// Regarding #3 above: mutations of arrays via .push or .splice actually modify the .length before the set handler is invoked
				// so in order to accurately report the correct previousValue for the .length, we have to use a helper property.
				if (targetProp !== value || originalChange === false || (property === "length" && target instanceof Array && target.__length !== value)) {

					var foundObservable = true;

					var typeOfTargetProp = (typeof targetProp);

					// determine if we're adding something new or modifying some that already existed
					var type = "update";
					if (typeOfTargetProp === "undefined") type = "add";

					// store the change that just occurred. it is important that we store the change before invoking the other proxies so that the previousValue is correct
					changes.push({
						"type":type
						,"target":target
						,"property":property
						,"newValue":value
						,"previousValue":receiver[property]
						,"currentPath":_getPath(target, property)
						,"jsonPointer":_getPath(target, property, true)
						,"proxy":proxy
					});

					// mutations of arrays via .push or .splice actually modify the .length before the set handler is invoked
					// so in order to accurately report the correct previousValue for the .length, we have to use a helper property.
					if (property === "length" && target instanceof Array && target.__length !== value) {
						changes[changes.length-1].previousValue = target.__length;
						target.__length = value;
					}

					// !!IMPORTANT!! if this proxy was the first proxy to receive the change, then we need to go check and see
					// if there are other proxies for the same project. if there are, then we will modify those proxies as well so the other
					// observers can be modified of the change that has occurred.
					if (originalChange === true) {

						// because the value actually differs than the previous value
						// we need to store the new value on the original target object,
						// but only as long as changes have not been paused
						if (!observable.changesPaused) target[property] = value;


						foundObservable = false;

						var targetPosition = target.__targetPosition;
						var z = targetsProxy[targetPosition].length;

						// find the parent target for this observable -- if the target for that observable has not been removed
						// from the targets array, then that means the observable is still active and we should notify the observers of this change
						while (z--) {
							if (observable === targetsProxy[targetPosition][z].observable) {
								if (targets[targetsProxy[targetPosition][z].observable.parentTarget.__targetPosition] !== null) {
									foundObservable = true;
									break;
								}
							}
						}

						// if we didn't find an observable for this proxy, then that means .remove(proxy) was likely invoked
						// so we no longer need to notify any observer function about the changes, but we still need to update the
						// value of the underlying original objects see below: target[property] = value;
						if (foundObservable) {

							// loop over each proxy and see if the target for this change has any other proxies
							var currentTargetProxy = targetsProxy[targetPosition];
							for (var b = 0, l = currentTargetProxy.length; b < l; b++) {
								// if the same target has a different proxy
								if (currentTargetProxy[b].proxy !== proxy) {

									// !!IMPORTANT!! store the proxy as a duplicate proxy (dupProxy) -- this will adjust the behavior above appropriately (that is,
									// prevent a change on dupProxy from re-triggering the same change on other proxies)
									dupProxy = currentTargetProxy[b].proxy;

									// invoke the same change on the different proxy for the same target object. it is important that we make this change *after* we invoke the same change
									// on any other proxies so that the previousValue can show up correct for the other proxies
									currentTargetProxy[b].proxy[property] = value;

								}
							}

							// if the property being overwritten is an object, then that means this observable
							// will need to stop monitoring this object and any nested objects underneath the overwritten object else they'll become
							// orphaned and grow memory usage. we execute this on a setTimeout so that the clean-up process does not block
							// the UI rendering -- there's no need to execute the clean up immediately
							setTimeout(function() {

								if (typeOfTargetProp === "object" && targetProp !== null) {

									// check if the to-be-overwritten target property still exists on the target object
									// if it does still exist on the object, then we don't want to stop observing it. this resolves
									// an issue where array .sort() triggers objects to be overwritten, but instead of being overwritten
									// and discarded, they are shuffled to a new position in the array
									var keys = Object.keys(target);
									for (var i = 0, l = keys.length; i < l; i++) {
										if (target[keys[i]] === targetProp) return;
									}

									var stillExists = false;

									// now we perform the more expensive search recursively through the target object.
									// if we find the targetProp (that was just overwritten) still exists somewhere else
									// further down in the object, then we still need to observe the targetProp on this observable.
									(function iterate(target) {
										var keys = Object.keys(target);
										for (var i = 0, l = keys.length; i < l; i++) {

											var property = keys[i];
											var nestedTarget = target[property];

											if (nestedTarget instanceof Object && nestedTarget !== null) iterate(nestedTarget);
											if (nestedTarget === targetProp) {
												stillExists = true;
												return;
											}
										};
									})(target);

									// even though targetProp was overwritten, if it still exists somewhere else on the object,
									// then we don't want to remove the observable for that object (targetProp)
									if (stillExists === true) return;

									// loop over each property and recursively invoke the `iterate` function for any
									// objects nested on targetProp
									(function iterate(obj) {

										var keys = Object.keys(obj);
										for (var i = 0, l = keys.length; i < l; i++) {
											var objProp = obj[keys[i]];
											if (objProp instanceof Object && objProp !== null) iterate(objProp);
										}

										// if there are any existing target objects (objects that we're already observing)...
										var c = -1;
										for (var i = 0, l = targets.length; i < l; i++) {
											if (obj === targets[i]) {
												c = i;
												break;
											}
										}
										if (c > -1) {

											// ...then we want to determine if the observables for that object match our current observable
											var currentTargetProxy = targetsProxy[c];
											var d = currentTargetProxy.length;

											while (d--) {
												// if we do have an observable monitoring the object thats about to be overwritten
												// then we can remove that observable from the target object
												if (observable === currentTargetProxy[d].observable) {
													currentTargetProxy.splice(d,1);
													break;
												}
											}

											// if there are no more observables assigned to the target object, then we can remove
											// the target object altogether. this is necessary to prevent growing memory consumption particularly with large data sets
											if (currentTargetProxy.length == 0) {
												// targetsProxy.splice(c,1);
												targets[c] = null;
											}
										}

									})(targetProp)
								}
							},10000);
						}

						// TO DO: the next block of code resolves test case #29, but it results in poor IE11 performance with very large objects.
						// UPDATE: need to re-evaluate IE11 performance due to major performance overhaul from 12/23/2018.
						//
						// if the value we've just set is an object, then we'll need to iterate over it in order to initialize the
						// observers/proxies on all nested children of the object
						/* if (value instanceof Object && value !== null) {
							(function iterate(proxy) {
								var target = proxy.__getTarget;
								var keys = Object.keys(target);
								for (var i = 0, l = keys.length; i < l; i++) {
									var property = keys[i];
									if (target[property] instanceof Object && target[property] !== null) iterate(proxy[property]);
								};
							})(proxy[property]);
						}; */

					};

					if (foundObservable) {
						// notify the observer functions that the target has been modified
						_notifyObservers(changes.length);
					}

				}
				return true;
			}
		}

		var __targetPosition = target.__targetPosition;
		if (!(__targetPosition > -1)) {
			Object.defineProperty(target, "__targetPosition", {
				value: targets.length
				,writable: false
				,enumerable: false
				,configurable: false
			});
		}

		// create the proxy that we'll use to observe any changes
		var proxy = new Proxy(target, handler);

		// we don't want to create a new observable if this function was invoked recursively
		if (observable === null) {
			observable = {"parentTarget":target, "domDelay":domDelay, "parentProxy":proxy, "observers":[],"paused":false,"path":path,"changesPaused":false};
			observables.push(observable);
		}

		// store the proxy we've created so it isn't re-created unnecessarily via get handler
		var proxyItem = {"target":target,"proxy":proxy,"observable":observable};

		// if we have already created a Proxy for this target object then we add it to the corresponding array
		// on targetsProxy (targets and targetsProxy work together as a Hash table indexed by the actual target object).
		if (__targetPosition > -1) {

			// the targets array is set to null for the position of this particular object, then we know that
			// the observable was removed some point in time for this object -- so we need to set the reference again
			if (targets[__targetPosition] === null) {
				targets[__targetPosition] = target;
			}

			targetsProxy[__targetPosition].push(proxyItem);

		// else this is a target object that we had not yet created a Proxy for, so we must add it to targets,
		// and push a new array on to targetsProxy containing the new Proxy
		} else {
			targets.push(target);
			targetsProxy.push([proxyItem]);
		}

		return proxy;
	};

	/**
	 * @typedef {object} ObservableSlimChange Observed change.
	 * @property {"add"|"update"|"delete"} type Change type.
	 * @property {string} property Property name.
	 * @property {string} currentPath Property path with the dot notation (e.g. `foo.0.bar`).
	 * @property {string} jsonPointer Property path with the JSON pointer syntax (e.g. `/foo/0/bar`). See https://datatracker.ietf.org/doc/html/rfc6901.
	 * @property {object} target Target object.
	 * @property {ProxyConstructor} proxy Proxy of the target object.
	 * @property {*} newValue New value of the property.
	 * @property {*} [previousValue] Previous value of the property
	 */

	return {
		/**
		 * Create a new ES6 `Proxy` whose changes we can observe through the `observe()` method.
		 * @param {object} target Plain object that we want to observe for changes.
		 * @param {boolean|number} domDelay If `true`, then the observed changes to `target` will be batched up on a 10ms delay (via `setTimeout()`).
		 * If `false`, then the `observer` function will be immediately invoked after each individual change made to `target`. It is helpful to set
		 * `domDelay` to `true` when your `observer` function makes DOM manipulations (fewer DOM redraws means better performance). If a number greater
		 * than zero, then it defines the DOM delay in milliseconds.
		 * @param {function(ObservableSlimChange[])} [observer] Function that will be invoked when a change is made to the proxy of `target`.
		 * When invoked, this function is passed a single argument: an array of `ObservableSlimChange` detailing each change that has been made.
		 * @returns {ProxyConstructor} Proxy of the target object.
		 */
		create: function(target, domDelay, observer) {

			// test if the target is a Proxy, if it is then we need to retrieve the original object behind the Proxy.
			// we do not allow creating proxies of proxies because -- given the recursive design of ObservableSlim -- it would lead to sharp increases in memory usage
			if (target.__isProxy === true) {
				var target = target.__getTarget;
				//if it is, then we should throw an error. we do not allow creating proxies of proxies
				// because -- given the recursive design of ObservableSlim -- it would lead to sharp increases in memory usage
				//throw new Error("ObservableSlim.create() cannot create a Proxy for a target object that is also a Proxy.");
			}

			// fire off the _create() method -- it will create a new observable and proxy and return the proxy
			var proxy = _create(target, domDelay);

			// assign the observer function
			if (typeof observer === "function") this.observe(proxy, observer);

			// recursively loop over all nested objects on the proxy we've just created
			// this will allow the top observable to observe any changes that occur on a nested object
			(function iterate(proxy) {
				var target = proxy.__getTarget;
				var keys  = Object.keys(target);
				for (var i = 0, l = keys.length; i < l; i++) {
					var property = keys[i];
					if (target[property] instanceof Object && target[property] !== null) iterate(proxy[property]);
				}
			})(proxy);

			return proxy;

		},

		/**
		 * Add a new observer function to an existing proxy.
		 * @param {ProxyConstructor} proxy An ES6 `Proxy` created by the `create()` method.
		 * @param {function(ObservableSlimChange[])} observer Function that will be invoked when a change is made to the proxy of `target`.
		 * When invoked, this function is passed a single argument: an array of `ObservableSlimChange` detailing each change that has been made.
		 * @returns {void} Does not return any value.
		 */
		observe: function(proxy, observer) {
			// loop over all the observables created by the _create() function
			var i = observables.length;
			while (i--) {
				if (observables[i].parentProxy === proxy) {
					observables[i].observers.push(observer);
					break;
				}
			};
		},

		/**
		 * Prevent any observer functions from being invoked when a change occurs to a proxy.
		 * @param {ProxyConstructor} proxy An ES6 `Proxy` created by the `create()` method.
		 * @returns {void} Does not return any value.
		 */
		pause: function(proxy) {
			var i = observables.length;
			var foundMatch = false;
			while (i--) {
				if (observables[i].parentProxy === proxy) {
					observables[i].paused = true;
					foundMatch = true;
					break;
				}
			};

			if (foundMatch == false) throw new Error("ObseravableSlim could not pause observable -- matching proxy not found.");
		},

		/**
		 * Resume execution of any observer functions when a change is made to a proxy.
		 * @param {ProxyConstructor} proxy An ES6 `Proxy` created by the `create()` method.
		 * @returns {void} Does not return any value.
		 */
		resume: function(proxy) {
			var i = observables.length;
			var foundMatch = false;
			while (i--) {
				if (observables[i].parentProxy === proxy) {
					observables[i].paused = false;
					foundMatch = true;
					break;
				}
			};

			if (foundMatch == false) throw new Error("ObseravableSlim could not resume observable -- matching proxy not found.");
		},

		/**
		 * Prevent any changes (i.e., `set`, and `deleteProperty`) from being written to the target object.
		 * However, the observer functions will still be invoked to let you know what changes **WOULD** have been made.
		 * This can be useful if the changes need to be approved by an external source before the changes take effect.
		 * @param {ProxyConstructor} proxy An ES6 `Proxy` created by the `create()` method.
		 * @returns {void} Does not return any value.
		 */
		pauseChanges: function(proxy){
			var i = observables.length;
			var foundMatch = false;
			while (i--) {
				if (observables[i].parentProxy === proxy) {
					observables[i].changesPaused = true;
					foundMatch = true;
					break;
				}
			};

			if (foundMatch == false) throw new Error("ObseravableSlim could not pause changes on observable -- matching proxy not found.");
		},

		/**
		 * Resume the changes that were taking place prior to the call to `pauseChanges()` method.
		 * @param {ProxyConstructor} proxy An ES6 `Proxy` created by the `create()` method.
		 * @returns {void} Does not return any value.
		 */
		resumeChanges: function(proxy){
			var i = observables.length;
			var foundMatch = false;
			while (i--) {
				if (observables[i].parentProxy === proxy) {
					observables[i].changesPaused = false;
					foundMatch = true;
					break;
				}
			};

			if (foundMatch == false) throw new Error("ObseravableSlim could not resume changes on observable -- matching proxy not found.");
		},

		/**
		 * Remove the observable and proxy thereby preventing any further callback observers for changes occurring to the target object.
		 * @param {ProxyConstructor} proxy An ES6 `Proxy` created by the `create()` method.
		 * @returns {void} Does not return any value.
		 */
		remove: function(proxy) {

			var matchedObservable = null;
			var foundMatch = false;

			var c = observables.length;
			while (c--) {
				if (observables[c].parentProxy === proxy) {
					matchedObservable = observables[c];
					foundMatch = true;
					break;
				}
			};

			var a = targetsProxy.length;
			while (a--) {
				var b = targetsProxy[a].length;
				while (b--) {
					if (targetsProxy[a][b].observable === matchedObservable) {
						targetsProxy[a].splice(b,1);

						// if there are no more proxies for this target object
						// then we null out the position for this object on the targets array
						// since we are essentially no longer observing this object.
						// we do not splice it off the targets array, because if we re-observe the same
						// object at a later time, the property __targetPosition cannot be redefined.
						if (targetsProxy[a].length === 0) {
							targets[a] = null;
						};
					}
				};
			};

			if (foundMatch === true) {
				observables.splice(c,1);
			}
		}
	};
})();

// Export in a try catch to prevent this from erroring out on older browsers
try { module.exports = ObservableSlim; } catch (err) {};