With the continuous development of JavaScript, front-end engineers have gradually become aware of some problems in JavaScript itself, such as the lack of type checking and modularity, which often cause confusion and errors in large projects. In order to solve these problems, TypeScript came into being and became an increasingly popular language in front-end development.

In the field of back-end development, PHP has always been an extremely popular scripting language. Therefore, combining TypeScript to develop PHP applications will be a very good choice. This article explains how to write better code using TypeScript in PHP.

1. Why use TypeScript

1. Type checking

TypeScript emphasizes type safety and provides many excellent features, such as type checking, interfaces and abstract classes. Moreover, it also supports inheritance and generics, making your code clearer and easier to understand.

2. Error catching

TypeScript can find problems when compiling, not when errors occur when your code is running. This means you can check for and fix errors before going live, avoiding downtime.

3. Good engineering

TypeScript’s engineering support is excellent. Developers can easily use modular facilities in TypeScript, automatically reference type definition files, and complete code encapsulation and other functions. .

2. How to use TypeScript to write PHP code

1. Install dependencies

First, TypeScript needs to be installed. For the node.js environment, you can install it with the following command:

npm install -g typescript

2. Configuration file

Using TypeScript in PHP requires dealing with two issues: how to compile TypeScript, and how to convert the TypeScript module Integrate with PHP applications.

Create a TypeScript configuration file named tsconfig.json in the root directory of the project. This file tells the TypeScript compiler how to compile TypeScript code into JavaScript code. A basic configuration file can be as follows:

{
   "compilerOptions": {
       "target": "es2015",
       "module": "commonjs",
       "outDir": "dist",
       "sourceMap": true,
       "esModuleInterop": true,
       "resolveJsonModule": true,
       "declaration": true
   },
   "exclude": [
       "node_modules",
       "tests"
   ]
}

Among them, compilerOptions are the compiler options and can be modified according to the specific situation.

3. Write code

You can use PHP’s built-in functions and extension classes in TypeScript. For example, you can use the PDO extension to interact with the MySQL database. The sample code is as follows:

import * as mysql from 'mysql';

class Database {
    private conn: mysql.Connection;
 
    constructor(
        private readonly host: string,
        private readonly user: string,
        private readonly password: string,
        private readonly database: string
    ) {
        this.conn = mysql.createConnection({
            host,
            user,
            password,
            database
        });
    }
 
    public async connect(): Promise<mysql.Connection> {
        await new Promise(resolve => {
            this.conn.connect(err => {
                if (err) {
                    console.error(err);
                }
                resolve();
            });
        });
 
        return this.conn;
    }
 
    public async close(): Promise<void> {
        await new Promise(resolve => {
            this.conn.end(err => {
                if (err) {
                    console.error(err);
                }
                resolve();
            });
        });
    }
 
    public async query(sql: string, params: any[]): Promise<any> {
        return new Promise((resolve, reject) => {
            this.conn.query(sql, params, (err, res, fields) => {
                if (err) {
                    console.error(err);
                    reject(err);
                }
                resolve(res);
            });
        });
    }
}

4. Compile the code

After creating the TypeScript configuration file and code, you need to run the following command to TypeScript code is compiled into JavaScript code:

tsc

After running this command, the TypeScript compiler will compile all TypeScript files into JavaScript files and place them in a directory called outDir.

5. Integrate into PHP projects

The final step in using TypeScript in a PHP project is to integrate the compiled JavaScript files into your PHP application. TypeScript can be compiled into JavaScript, and then the compiled JavaScript files can be introduced into your PHP application using PHP's require() or include() functions.

3. Summary

Using TypeScript to write PHP code allows developers to develop PHP applications more efficiently. At the same time, they can take advantage of the type checking, error trapping and engineering support provided in TypeScript. features to avoid many common problems. Although this writing method needs to adapt to a certain development environment, it is a good choice for front-end developers transitioning to back-end, or developers who want to use TypeScript to improve PHP development efficiency.

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