generator module and co

Class // Array Generator

// array of classes generator 
function FNS () { 
	the let obj = {0: 1,1: 2,2 &:. 3, length:. 3}, [Symbol.iterator]: function () { 
		the let index = 0; 
		the let that the this =; 
		return { 
			Next () { 
				return { 
					value: that [index], 
					DONE: === that.length index ++ 
				} 
			} 
		} 
	} 
	the let ARR = [... obj]; 
	the console.log (Array.isArray (ARR ), ARR); 
} 

// automate Next 
function FNS () { 
	// add the iterative approach to array- 
	let obj = {0: 1,1: 2,2: 3, length: 3}, [Symbol.iterator] : function () { 
		the let index = 0; 
		the let = that the this; 
		the while (index === that.length) { 
			the yield that [index ++] 
		} 
	}
	let arr = [...obj];
	console.log(Array.isArray(arr), arr);
}
fns(1,2,3,4,5)

　　

#### co Module

// generator + promise 来使用
let fs = require('fs').promises;

// promise 要通过then  generator 可以省略then方法
function* read() {
    // try{
        let content = yield fs.readFile('./name.txt','utf8');
        let age = yield fs.readFile(content,'utf8');
        let a = yield age + 100;
        return a;
    // }catch(err){
    //     console.log(err);
    // }
}
// co 库

function co(it){
    return new Promise((resolve,reject)=>{
        // 异步迭代 next
        function next(data){
           let {value,done} = it.next(data);
           if(!done){
               Promise.resolve(value).then(data=>{
                  next(data)
               },reject);
           }else{
                resolve(value);
           }
        }
        next();
    });
}
co(read()).then(data=>{
    console.log(data);
});

　　

#### for the first time next invalid, and to stop the local yield. next to where the value is copied to the copy of the value of yield.