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.

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