Can a javascript function have no name?

In JavaScript, a function can have no name; a function without a name is called an "anonymous function". The function only contains the function keyword, parameters and function body, and the syntax is "function ([args]){statements} ".

The operating environment of this tutorial: windows7 system, javascript version 1.8.5, Dell G3 computer.

In JavaScript, functions can have no name.

A function without a name is called an "anonymous function" and contains only the function keyword, parameters and function body. The specific usage is as follows:

function ([args]) {
statements
}

Example 1

The following code defines an anonymous function.

function (a, b) {  //匿名函数
    return a + b;
}

In the above code, function literals are basically the same as using function statements to define function structures, and their structures are fixed. However, the function literal does not specify a function name, but directly uses the keyword function to represent the structure of the function. This kind of function is also called an anonymous function.

Example 2

Anonymous function is an expression, that is, a function expression, not a statement of function structure. Next, assign the anonymous function as a value to the variable f.

//把函数作为一个值直接赋值给变量 f
var f = function (a, b) {
    return a + b;
};

When the function structure is assigned to a variable as a value, the variable can be called as a function, and the variable points to the anonymous function.

console.log(f(1,2));  //返回值3

Example 3

Anonymous functions serve as values ​​and can participate in more complex expression operations. For the above example, you can use the following code to complete the integrated operation of function definition and call.

console.log(  //把函数作为一个操作数进行调用
    (function (a,b) {
        return a + b;
    })(1, 2));  //返回数值3

The role of anonymous functions:

1. Closures can be implemented through anonymous functions. Closures will be explained in the following articles. A quick introduction here: a closure is a function that can access variables defined within the function scope. To create a closure, you often need to use an anonymous function.

2. Simulate block-level scope and reduce global variables. After executing the anonymous function, the corresponding variables stored in the memory will be destroyed, thereby saving memory. Furthermore, in large-scale multi-person development projects, using block-level scope will greatly reduce the problem of naming conflicts, thereby avoiding catastrophic consequences. Developers no longer have to worry about messing up the global scope.

【Related recommendations: javascript video tutorial, web front-end】

The above is the detailed content of Can a javascript function have no name?. For more information, please follow other related articles on the PHP Chinese website!