nodejs same interface but different functions

NodeJS is a very powerful server-side JavaScript runtime environment that allows us to develop back-end applications using JavaScript, which makes NodeJS a very useful skill for front-end developers.

When developing applications using NodeJS, we usually need to use different functions in the same interface. NodeJS provides a variety of ways to achieve this, and we will introduce several of them below.

1. Using callback functions

Callback functions are the most commonly used method in NodeJS to implement calls to different functions in the same interface. The callback function is actually a function passed in as a parameter of another function. After the first function is completed, the second function will be called.

The following is a simple example showing how to use different functions in the same interface:

function firstFunction(callback) {
  setTimeout(function () {
    console.log("执行第一个函数");
    callback();
  }, 1000);
}

function secondFunction() {
  console.log("执行第二个函数");
}

firstFunction(secondFunction);

In this example, the firstFunction function accepts a callback function as a parameter. When the first After the first function completes, the second function will be called.

2. Using Promise

Promise is a technology that solves asynchronous programming problems. It can be used to execute different functions in the same interface. Promise allows us to handle asynchronous operations more elegantly. It packages asynchronous operations into an object and implements sequential execution of asynchronous operations through chain calls.

The following is an example of using Promise:

function firstFunction() {
  return new Promise(function (resolve, reject) {
    setTimeout(function () {
      console.log("执行第一个函数");
      resolve();
    }, 1000);
  });
}

function secondFunction() {
  console.log("执行第二个函数");
}

firstFunction().then(secondFunction);

In this example, firstFunction returns a Promise object. In the Promise object, we wrap the asynchronous operation into a function. After the first function completes, the resolve method is called, which indicates that the asynchronous operation has completed. Then, we called the then method in the second function to implement the sequential execution of asynchronous operations through chain calls.

3. Using async/await

async/await is a new feature introduced in ES2017, which can make asynchronous operation code look more like synchronous code. Using async/await allows us to implement different functions in the same interface more easily.

The following is an example of using async/await:

function firstFunction() {
  return new Promise(function (resolve, reject) {
    setTimeout(function () {
      console.log("执行第一个函数");
      resolve();
    }, 1000);
  });
}

function secondFunction() {
  console.log("执行第二个函数");
}

async function run() {
  await firstFunction();
  secondFunction();
}

run();

In this example, we define an asynchronous function named run. This function uses the async keyword to declare that it is An asynchronous function, and then we use the await keyword inside the function to wait for the asynchronous function to complete. In this example, we wait for the first function to complete before executing the second function.

Summary

Through callback functions, Promise and async/await, we can implement different functions in the same interface. Each method has its own advantages and disadvantages, and we can choose one of them according to the actual situation.

Callback functions are very common, and they can help us handle asynchronous operations, but when we use multiple nested callback functions, the code will become very difficult to maintain. Promise can help us solve the callback hell problem, but it may be difficult for beginners to understand. async/await is the latest asynchronous solution. By using it, we can make asynchronous code look more like synchronous code.

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