Created
January 31, 2014 22:42
-
-
Save beyond-code-github/8744757 to your computer and use it in GitHub Desktop.
Change tracking implementation for knockout.js supporting complex objects
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
var getObjProperties = function (obj) { | |
var objProperties = []; | |
var val = ko.utils.unwrapObservable(obj); | |
if (val !== null && typeof val === 'object') { | |
for (var i in val) { | |
if (val.hasOwnProperty(i)) objProperties.push({ "name": i, "value": val[i] }); | |
} | |
} | |
return objProperties; | |
}; | |
var traverseObservables = function (obj, action) { | |
ko.utils.arrayForEach(getObjProperties(obj), function (observable) { | |
if (observable && observable.value && !observable.value.nodeType && ko.isObservable(observable.value)) { | |
action(observable); | |
} | |
}); | |
}; | |
ko.extenders.trackChange = function (target, track) { | |
if (track) { | |
target.hasValueChanged = ko.observable(false); | |
target.hasDirtyProperties = ko.observable(false); | |
target.isDirty = ko.computed(function () { | |
return target.hasValueChanged() || target.hasDirtyProperties(); | |
}); | |
var unwrapped = target(); | |
if ((typeof unwrapped == "object") && (unwrapped !== null)) { | |
traverseObservables(unwrapped, function (obj) { | |
applyChangeTrackingToObservable(obj.value); | |
obj.value.isDirty.subscribe(function (isdirty) { | |
if (isdirty) target.hasDirtyProperties(true); | |
}); | |
}); | |
} | |
target.originalValue = target(); | |
target.subscribe(function (newValue) { | |
// use != not !== so numbers will equate naturally | |
target.hasValueChanged(newValue != target.originalValue); | |
target.hasValueChanged.valueHasMutated(); | |
}); | |
if (!target.getChanges) { | |
target.getChanges = function (newObject) { | |
var obj = target(); | |
if ((typeof obj == "object") && (obj !== null)) { | |
if (target.hasValueChanged()) { | |
return ko.mapping.toJS(obj); | |
} | |
return getChangesFromModel(obj); | |
} | |
return target(); | |
}; | |
} | |
} | |
return target; | |
}; | |
var applyChangeTrackingToObservable = function (observable) { | |
// Only apply to basic writeable observables | |
if (observable && !observable.nodeType && !observable.refresh && ko.isObservable(observable)) { | |
if (!observable.isDirty) observable.extend({ trackChange: true }); | |
} | |
}; | |
var applyChangeTracking = function (obj) { | |
var properties = getObjProperties(obj); | |
ko.utils.arrayForEach(properties, function (property) { | |
applyChangeTrackingToObservable(property.value); | |
}); | |
}; | |
var getChangesFromModel = function (obj) { | |
var changes = null; | |
var properties = getObjProperties(obj); | |
ko.utils.arrayForEach(properties, function (property) { | |
if (property.value != null && typeof property.value.isDirty != "undefined" && property.value.isDirty()) { | |
changes = changes || {}; | |
changes[property.name] = property.value.getChanges(); | |
} | |
}); | |
return changes; | |
}; | |
var viewModel = { | |
Name: ko.observable("Pete"), | |
Age: ko.observable(29), | |
Skills: ko.observable({ | |
Tdd: ko.observable(true), | |
Knockout: ko.observable(true), | |
ChangeTracking: ko.observable(false), | |
Languages: ko.observable({ | |
Csharp: ko.observable(false), | |
Javascript: ko.observable(false) | |
}), | |
}), | |
Occupation: ko.observable("Developer") | |
}; | |
applyChangeTracking(viewModel); | |
viewModel.Skills().ChangeTracking(true); | |
viewModel.Skills().Languages({ | |
Csharp: ko.observable(true), | |
Javascript: ko.observable(true), | |
}); | |
console.log(getChangesFromModel(viewModel)); |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Your blog post hasn't been updated for the new username on gist.
https://roysvork.wordpress.com/2014/01/12/tracking-changes-to-complex-viewmodels-with-knockout-js/