Error with breeze 1.4.11 and IE8 - breeze

Question

Trying to download data with breeze 1.4.11 and IE8 throws the following exception:
Unable to either parse or import metadata: getters & setters can not be defined on this javascript engine
The error is caused by line 173 of b00_breeze.modelLibrary.backingStore.js
Created a GitHub repo to reproduce the bug.

Answer 1

Breeze uses the ViewModel of the hosting MVVM framework. That’s generally a good decision. Additionally, change tracking on entities is a fundamental concept of breeze.js (same for Entity Framework). It’s an easy task to track changes if the MVVM framework uses Observables with real getter and setters (e.g. Knockout). AngularJS on the other hands works with plain JavaScript objects. This makes change tracking difficulty. The only two reliable ways are ES5-properties (simple, but not supported by IE8) or a very deep integration in the $digest cycle. The breeze-team took the first-choice - what a pity for projects that have to support IE8!
Ok, let's analyze the root cause of the problem: change tracking
Do you really need that feature? At least in our project we decided for breeze.js/OData for reading and for a more "restful" approach when it comes to writing. If you don’t need those advanced features, than the following script should solve the issue:
/********************************************************
* A replacement for the "backingStore" modelLibrary
*
* This is a bare version of the original backingStore,
* without ANY change tracking - that's why it will work in IE8!
* (Object.defineProperty not required any more)
*
* This adapter is a "drop in" replacement for the "backingStore" adapter in Breeze core.
* It has the same adapter name so it will silently replace the original "backingStore" adapter
* when you load this script AFTER the breeze library.
* WARNING: For obvious reasons a lot of breeze magic will be lost!
*
* Author: Johannes Hoppe / haushoppe-its.de
*
* Copyright 2014 IdeaBlade, Inc. All Rights Reserved.
* Use, reproduction, distribution, and modification of this code is subject to the terms and
* conditions of the IdeaBlade Breeze license, available at http://www.breezejs.com/license
******************************************************/
(function (definition, window) {
if (window.breeze) {
definition(window.breeze);
} else if (typeof require === "function" && typeof exports === "object" && typeof module === "object") {
// CommonJS or Node
var b = require('breeze');
definition(b);
} else if (typeof define === "function" && define["amd"] && !window.breeze) {
// Requirejs / AMD
define(['breeze'], definition);
} else {
throw new Error("Can't find breeze");
}
}(function (breeze) {
"use strict";
var core = breeze.core;
var ctor = function () {
this.name = "backingStore";
this.A_BIG_FAT_WARNING = "This is a bare version of the backingStore! Change tracking won't work!";
};
var protoFn = ctor.prototype;
protoFn.initialize = function() {
};
protoFn.getTrackablePropertyNames = function (entity) {
var names = [];
for (var p in entity) {
if (p === "entityType") continue;
if (p === "_$typeName") continue;
var val = entity[p];
if (!core.isFunction(val)) {
names.push(p);
}
}
return names;
};
protoFn.initializeEntityPrototype = function (proto) {
proto.getProperty = function (propertyName) {
return this[propertyName];
};
proto.setProperty = function (propertyName, value) {
this[propertyName] = value;
return this;
};
};
// This method is called when an EntityAspect is first created - this will occur as part of the entityType.createEntity call.
// which can be called either directly or via standard query materialization
// entity is either an entity or a complexObject
protoFn.startTracking = function (entity, proto) {
// assign default values to the entity
var stype = entity.entityType || entity.complexType;
stype.getProperties().forEach(function (prop) {
var propName = prop.name;
var val = entity[propName];
if (prop.isDataProperty) {
if (prop.isComplexProperty) {
if (prop.isScalar) {
val = prop.dataType._createInstanceCore(entity, prop);
} else {
val = breeze.makeComplexArray([], entity, prop);
}
} else if (!prop.isScalar) {
val = breeze.makePrimitiveArray([], entity, prop);
} else if (val === undefined) {
val = prop.defaultValue;
}
} else if (prop.isNavigationProperty) {
if (val !== undefined) {
throw new Error("Cannot assign a navigation property in an entity ctor.: " + prop.Name);
}
if (prop.isScalar) {
// TODO: change this to nullstob later.
val = null;
} else {
val = breeze.makeRelationArray([], entity, prop);
}
} else {
throw new Error("unknown property: " + propName);
}
entity[propName] = val;
});
};
breeze.config.registerAdapter("modelLibrary", ctor);
}, this));
Download at: https://gist.github.com/JohannesHoppe/72d7916aeb08897bd256
This is a bare version of the original backingStore, without ANY change tracking - that's why it will work in IE8! (Object.defineProperty not required any more) This adapter is a "drop in" replacement for the "backingStore" adapter in Breeze core. It has the same adapter name so it will silently replace the original "backingStore" adapter when you load the script AFTER the breeze library.
Here is a demo to proof the functionality:
http://jsfiddle.net/Johannes_Hoppe/bcav9hzL/5/
JsFiddle does not support IE8, please use this direct link:
http://jsfiddle.net/Johannes_Hoppe/bcav9hzL/5/embedded/result/
Cheers!

Answer 2

The Breeze 'backingStore' model library is explicitly not supported in IE8. This is because the 'backingStore' implementation requires the full javascript 'Object.defineProperty' capability which is not available in IE8 and cannot be provided by any shim.
That said, the breeze 'knockout' and 'backbone' model library adapters should both work with IE8.
Also see: http://www.breezejs.com/documentation/prerequisites