AngularJS is the preference of many web developers when it comes to the creation of single-page applications. There are so many challenges that corporations and individual developers face whenever they are creating such applications, but the use of AngularJS makes it considerable easier for them. With AngularJS, you will enjoy the experience of developing and testing single-page applications because it provides a framework for the side of the client model-view –controller and architects model-view-view model. It also provides components that are mainly used in the creation of rich internet applications.
We are already familiar with this technology as we have covered many topics on this framework in past. At first it would be really great if you get the clear idea of why you must use AngularJS for your next project and then you can check out our popular post on 15 websites to learn AngularJS.
As developers familiarize themselves with AngularJS, there are some potential mistakes that are made along the way. These mistakes could easily be avoided by taking a few precautions. Some of these mistakes are:
1. Declaring everything in AngularJS with anonymous functions
Always assign your objects and functions to a certain variable. It becomes very easy to manipulate and mutate them this way. This also makes the code tidy and easy to follow through and you can easily split the code into files, which is important during maintainability.
This should also be done for testability; as it becomes easy to test the code when everything is clearly declared. As a developer, you will have more expressive power on the code. It will make everything else easy for you at the end. Avoiding this mistake will give you many advantages and less issues when you are done.
2. Not using $applyAsync
Since there is no polling mechanism to call $digest() in AngularJS, it is just executed due to the existing directives. $applyAsync helps a lot in delaying the resolution of the expressions until the next cycle of $digest(). There is a manual and an automated way to use $applyAsync.
3. Using jQuery
jQuery is well known as a library for making DOM manipulation simple, for handling events and also for AJAX operations. AngularJS on the other hand is a framework that is used in the creation of scalable applications. It is all about development and testing of applications, therefore it cannot be used in augmentation of HTML pages. If that is the case, there is no need to use jQuery. What you should do is to just let your code go beyond HTML syntax just as it has been declared.
AngularJS has sufficient features and so, a developer should find out what features they have at their disposal before you opt to use jQuery. If you must have DOM manipulation, let it be done only in directives but this does not necessarily mean that jQuery has to be involved.
4. Not optimizing the application
This will definitely lead to AngularJS errors. Below is an example of a code within the controller that will work slow and probably give you an error:
this.maxPrice = '100';
this.price = '55’;
$scope.$watch('MC.price', function (newVal) {
if (newVal || newVal === 0) {
for (var i = 0; i < 987; i++) {
console.log('ALL YOUR BASE ARE BELONG TO US');
}
}
});
A solution that can be attempted would be on the input, by putting a timeout in place.
5. Using isolated scope more than its necessary
If you are looking for a directive, which you are sure will only be used in one location and you are also sure that it will not bring conflicts in the environment that it will be used in, there is no need to use an isolated scope as this could result to errors. One thing you should know is that you cannot use two isolated scope directives on one element. You will also deal with a number of issues when you are nesting, event processing or with inheritance.
6. Having more watchers than necessary
For every binding, AngularJS will create a watcher. On each digest phase, comparison and evaluation to previous bindings is done, a process which in AngularJS is referred to as dirty checking. Imagine how many watchers you will end up with in the end?
Limiting watchers is very easy if you do not watch scope models when you do not expect them to change. This will mean less watchers and few or no errors.
7. Ignoring controllerAs Syntax
$scope is usually used to assign a model to a controller object. Injecting scope is basically not the best way to do it. The best alternative, and the most efficient one is use of controllerAs Syntax. This is how you can define models using controllerAs Syntax:
function MainController($scope) {
this.foo = 1;
var that = this;
var setBar = function () {
// that.bar = {someProperty: 2};
this.bar = {someProperty: 2};
};
setBar.call(this);
// there are other conventions:
// var MC = this;
// setBar.call(this); when using 'this' inside setBar()
}
controllerAs Syntax gives you less confusing results especially when you are dealing with many nested scopes. It can also be used in so many other ways as you create your apps.
8. Doing Heavy processing
This may need you to use workers and could help resolve the common mistake of heavy processing that a lot of web developers make whenever they are using AngularJS. Heavy processing could lead to a frozen browser. You can avoid this issue by using web workers. You just have to implement it and then you can always process a large number of complex objects with ease.
9. Failing to use controllerAs Syntax as you should
controllerAs Syntax is quite useful and it can help you in the creation of better codes whenever you are building an application. One mistake you can make is not being able to utilize it fully for it benefits. It is the best tool to use when you are assigning a model to a controller tool. It has a host of other useful functions. Here is an illustration:
function MainController($scope) {
this.title = 'Some title';
$scope.$watch(angular.bind(this, function () {
return this.title;
}), function (newVal, oldVal) {
// handle changes
});
}
10. Not understanding resolves well
Basically, resolves will add to the time you need whenever you are loading a view. You are not supposed to overuse resolves because this will mean additional time for loading, which could result in a slow process.
Some of these mistakes happen when a web developer least expects. It helps when you have an idea of the cause and what to do to fix them, so that you do not find yourself starting all you’re coding from scratch.
