Shulou(Shulou.com)06/01 Report--

This article mainly introduces "web front-end programmer interview questions and answers". In daily operation, I believe many people have doubts about web front-end programmer interview questions and answers. Xiaobian consulted all kinds of materials and sorted out simple and easy-to-use operation methods, hoping to help you answer "web front-end programmer interview questions and answers". Next, please follow the editor to study!

1. Characteristics of Angular:

# 1 good application structure

In general, we don't have a clear structure for writing JavaScript. Although there is no problem when writing small applications, this is obviously not suitable for large-scale applications. With AngularJS, you can organize source code in MVC (Model-View-Controller) or MVVM (Model-View-View Model) patterns. AngularJS is a MVW framework where W stands for any project. You can organize your code modules, which can significantly improve the testability and maintainability of the application.

# 2 two-way data binding

Data binding is definitely one of the best features of AngularJS. You can declare the bound model to the HTML element. When the model changes, the view updates automatically, and vice versa. This reduces a lot of traditional boilerplate code and keeps the model and view synchronized.

# 3 instruction

The AngularJS directive allows you to quickly build applications using the new HTML syntax. You can create API for reusable custom components and instructions. For example, if you want to customize the date selector widget, you can create a component. If you want a strange file upload with a progress indicator, you can continue to create a component. Cool, isn't it?

# 4 HTML template

AngularJS uses HTML templates, which make things simple and allow designers and developers to work at the same time. Designers can create user interfaces in the usual way, and developers can use declarative binding syntax to easily match the data models of different UI components.

# 5 can be embedded, injected and tested

The best thing about AngularJS is that it is a good team member. It has never called for full commitment. According to AngularJS's official website, you can use AngularJS as much or as little as you need in your project. If you only need two-way data binding, you can introduce Angular, just use this feature.

AngularJS supports dependency injection right out of the box. If you need something, you just call Angular to inject it. It's that simple. This greatly improves testability because you can easily test simulated components.

AngularJS is always created with testability in mind. These modules and dependency injection systems make unit testing easier. In addition, AngularJS provides a tool called protractor, which makes end-to-end testing easy. Therefore, the code you develop is always testable and maintainable.

That's not all! AngularJS also provides more practical features, such as routing, filters, and animation.

2. The difference between slice,substr and substring

First, they both receive two parameters, slice and substring receive the start position and end position (excluding the end position), while substr receives the start position and the length of the string to be returned. Look directly at the following example:

1 var test = 'hello world'

two

3 alert (test.slice (4) 7); / / o w

4 alert (test.substring (4pm 7)); / / o w

5 alert (test.substr (4) 7); / / o world

One thing to note here is that substring takes the smaller of the two parameters as the starting position and the larger parameter as the end position.

Such as:

Alert (test.substring (7, 4)); / / o w

Then, when the received parameter is negative, slice adds the length of its string to the corresponding negative number as a parameter, substr simply takes the result of the addition of the first parameter and the length of the string as the first parameter, and substring simply converts all the negative parameters to 0. The test code is as follows:

1 var test = 'hello world'

two

3 alert (test.slice (- 3)); / / rld

4 alert (test.substring (- 3)); / / hello world

5 alert (test.substr (- 3)); / / rld

6 alert (test.slice (3mai Mui 4)); / / lo w

7 alert (test.substring (3mai Mui 4)); / / hel

8 alert (test.substr (3Morelink 4)); / / empty string

Note: IE has an error in handling negative values received by substr, which returns the original string.

At this point, the study on "what are the interview questions and answers for web front-end programmers" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.