Is the anonymous function in js only called once?

Anonymous functions in JavaScript are functions without function names and can be called multiple times. Advantages include: Use it and throw it away: Quickly write one-off or helper functions. Code simplification: Make the code simpler and more readable. Portability: Easily passed to other functions or used as callback functions.

Anonymous function in JavaScript

In JavaScript, an anonymous function refers to a function without a function name. They are usually defined using arrow function syntax (=>) or function expression syntax (function()).

Is the anonymous function only called once?

No, anonymous functions are not called just once. They can be called multiple times like normal functions.

Advantages of anonymous functions

• Use and discard: No need to define function names, you can quickly write one-time or auxiliary functions.
• Code Simplification: By avoiding the use of function names, you can make the code more concise and easier to read.
• Portability: Anonymous functions do not have names, so they can be easily passed to other functions or used as callback functions.

Usage of anonymous functions

Anonymous functions can be defined using the following syntax:

• Arrow function Syntax:

  <code class="javascript">const fn = () => {
  // 函数体
  };</code>

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• Function expression syntax:

  <code class="javascript">const fn = function() {
  // 函数体
  };</code>

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To call an anonymous function, you can use variables name (such as fn) just like calling any other function.

Example

<code class="javascript">// 即用即弃的示例
const doubledNumbers = [1, 2, 3].map((num) => num * 2);

// 作为回调函数的示例
setTimeout(() => {
  console.log("Hello, world!");
}, 1000);</code>

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