JS: extracting a resolve in Promise is not getting same result-CodePudding

I have the following block of code:

async done() => {
   return new Promise((resolve, reject) =>   {
       const events = new Map();
       events.set('CLOSE_CLICK_EVENT', () => {
         //other logic
         resolve(false); 
       });
   }
}

I am trying to removing the "other logic" to an external function. My other approach is below:

revised approach:

async done() => {
   return new Promise((resolve, reject) =>   {
       const events = new Map();
       events.set('CLOSE_CLICK_EVENT', () => {
          return this._doneCloseButtonHandler(events);
       });
   }
}

async _doneCloseButtonHandler(events) {
    //other logic
     return false;
}

The 2nd approach doesn't seem to be behaving the same way though -- why is the Promise being resolved differently? The Promise doesn't seem to be getting resolved when I try to use the 2nd approach.

CodePudding user response：

In the second approach, you are never calling the resolve function, so it cannot resolve, you need to chain it:

return this._doneCloseButtonHandler(events).then(resolve, reject);

Edit: based on OP's request, there is also a way to resolve within the _doneCloseButtonHandler function when you pass the resolve as argument:

return this._doneCloseButtonHandler(events, resolve)

// ...

function _doneCloseButtonHandler(event, resolve) {
    // ....
    resolve()
}

CodePudding user response：

To extract the "other logic", you should first refactor your function to

async done() {
   const _ = await new Promise((resolve, reject) =>   {
     const events = new Map();
     events.set('CLOSE_CLICK_EVENT', resolve);
     // do something with `events`
   });
   // other logic that should happen when the CLOSE_CLICK event occurs
   return false;
}

(the _ corresponds to whatever will be passed to the resolve call).

Then you can extract the other logic into a separate function.