What is the usage of generator in es6

In es6, generator is used to encapsulate asynchronous tasks. It is a container for asynchronous tasks, which allows the function to execute or pause according to the specified time; when defining the function, there is a between the function keyword and the function name. Asterisk (*), the syntax is "function *name(){..yield..}".

The operating environment of this tutorial: Windows 10 system, ECMAScript version 6.0, Dell G3 computer.

What is the usage of generator in es6

Generator is mainly asynchronous programming, used to encapsulate asynchronous tasks. It is a container for asynchronous tasks, allowing functions to be executed or paused at the time we specify.

The difference between defining a Generator function and defining an ordinary function is:

There is an * (asterisk) between the function keyword and the function name.

Yield is used inside the function to define the internal state of each function.

If there is a return statement inside the function, then it is the last state inside the function.

Use syntax:

function *name(){
...
yield; //需要暂停的时候加yield
...
yield;
...
}
const p = name();
p.next() //调用函数，执行到第一个yield处停止
p.next() //从上一个yeild开始执行，到下一个yield处为止

Let’s look at a simple example:

// 定义
function* sayHello() {
  yield 'hello';
  yield 'world';
  return 'ending';
}
// 调用
// 注意，hw获取到的值是一个遍历器对象
let g = sayHello();

The above example defines a Generator function named sayHello, which has two yields inside it expression and a return expression. Therefore, there are three states inside the function: hello, world and return statement (end execution). Finally, call this function to get a traverser object and assign it to the variable g.

The calling method of the Generator function is exactly the same as the ordinary function, function name (). The difference is:

• After the function is called, the internal code (starting from the first line) will not be executed immediately.

• There will be a return value after the function is called. This value is a pointer object pointing to the internal state. It is essentially a traverser object containing the internal state of the function.

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