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TypeScript & jQuery

Typescript​

tsc (typescript compiler) is a command-line tool that you can instal globally

tsc --init to create the typescript config

inferred type: to suggest indirectly that something is true

TypeScript is all about type safety. Nothing else. TS does NOT add any additional to JS. It only allows you to write JS in a more pricise manner.

2 + "2" = "22" is valid in JS. It is NOT type safety.

TS only add static checking to JS. Static checking có trong Java.

You write a lot more code in TS, and it is harder to read & understand. These are tradeoffs to avoid runtime error.

TS is a development tool, your production code still run in JS. It is installed as a dev dependency.

Types​

Type void

Don't use the keyword any in TS.

number is for numbers like 42. JavaScript does not have a special runtime value for integers, so there’s no equivalent to int or float - everything is simply number

You don't need to specify types when the context is obvious enough. This is called Type Inference in TS.

Type Aliases vs Interface​

2 cái này có similar syntax. Interface dùng nếu có function. Đọc official doc for more information.

Generics​

generic

tsconfig.json​

The presence of a tsconfig.json file in a directory indicates that the directory is the root of a TypeScript project. The tsconfig.json file specifies the root files and the compiler options required to compile the project.

jQuery​

One important thing to know is that jQuery is just a JavaScript library.

The jQuery library exposes its methods and properties via two properties of the window object called jQuery and $. $ is simply an alias for jQuery and it's often employed because it's shorter and faster to write.

jQuery có hàm .ready() để đảm bảo JS code run after the DOM is loaded. Nếu không dùng jQuery thì phải đặt <script> tag của main.js ở dòng cuối của <body> trong index.html

AJAX, which stands for Asynchronous JavaScript and XML, is a set of web development techniques used to create more dynamic and responsive web applications. Instead of requiring a full page reload for every user interaction, AJAX allows for the asynchronous exchange of data between the client (browser) and the server in the background.

References:

doc trên jquery.com hơi khó hiểu cho beginner

doc trên W3school more beginner friendly