ES6 链接访问以前的方法

Question

I have a problem with ES6 Class Chaining. I have a class as in the example. I want to access baz() method callback. I want to use that callback inside WorkHard class. How can I do that?

 class WorkHard { constructor() { this.value_1 = [] this.value_2 = [] } foo(args) { this.value_1 = args; return this; } baz(cb) { this.value_1 = null; this.value_2 = null; return this; } zoo(args) { this.value_2 = args; return this; } }

 const WorkHard = new WorkHard(); WorkHard.foo('TestValue_1').baz(() => { console.log('This is baz() method content.'); }).zoo('TestValue_2')

Answer 1

You pass callback at first argument baz, so you can call it like this:

 class WorkHard { constructor() { this.value_1 = [] this.value_2 = [] } foo(args) { this.value_1 = args; return this; } baz(cb) { this.value_1 = null; this.value_2 = null; cb(); return this; } zoo(args) { this.value_2 = args; return this; } } const workHard = new WorkHard(); workHard .foo('TestValue_1') .baz(() => { console.log('This is baz() method content.'); }) .zoo('TestValue_2'); 

Answer 2

You're not calling cb anywhere inside your class. Also, your instance cannot have the same name as the class.

Just execute cb inside baz .

 class WorkHard { constructor() { this.value_1 = [] this.value_2 = [] } foo(args) { this.value_1 = args; console.log('foo called'); return this; } baz(cb) { this.value_1 = null; this.value_2 = null; cb(); return this; } zoo(args) { console.log('zoo called'); this.value_2 = args; return this; } } const workHard = new WorkHard(); workHard.foo('TestValue_1').baz(() => { console.log('This is baz() method content.'); }).zoo('TestValue_2')

If you want the callback to control the chaining flow, keep in mind a callback returns nothing by itself, so you would need to also return that function call instead of this

 // inside WorkHard
 baz(cb) {
   this.value_1 = null;
   this.value_2 = null;
   return cb(this);
 }


workHard.foo('TestValue_1').baz((instance) => {
  console.log('Workhard visible variables are', instance);
  return instance;
}).zoo('TestValue_2');