为什么我没有收到以下所有代码片段的“冗余返回等待”（ESLint：no-return-await）警告？

Question

I have below code paths which are giving the Redundant return await warning in "IntelliJ": ( https://eslint.org/docs/rules/no-return-await )

Note: I see -ve votes for my question. Most likely I am missing something basic - can you point out in comments/question what am I missing? I am spending a significant amount of time asking the question - it will be helpful if you add details for -ve votes.

 import {browser, By, element, promise, protractor} from 'protractor';
          async randomMethod(): Promise<string> {
            return await element.all(By.css('.random-class')).first().getText();
          }

 async randomMethod4()  {
     return await browser.driver.get(this.url);
  }

Please note that just removing the await in the above methods get rid of the warning (like following code snippet). But my question is why is it ok for the below methods to do "return await", but not for "above".

async randomMethod(): Promise<string> {
        return element.all(By.css('.random-class')).first().getText();
      }

Whereas the following code paths don't give the same warning:

  async randomMethod2(): Promise<number> {
    return await element.all(By.css('.mat-row')).count();
  }

  async randomMethod3() {
    return await element.all(By.css('.random-class')).first();
  }

I am trying to understand in detail the reason for warning even though my tests are passing as I may be missing something subtle here. Any thoughts are helpful.

return await element.all(By.css('.random-class')).first().getText();

Btw, following are the function definitions/prototypes:

first(): ElementFinder;

count(): wdpromise.Promise<number>;

getText(): promise.Promise<string>;

get(url: string): promise.Promise<void>;

Answer 1

async functions always return a Promise, even if you don't await inside them. Since they always return a Promise you always have to "unwrap them" at the calling site (either by using await or .then()) in order to get the value or do something when it resolves.

When you use return await you are "uwrapping" a promise only for the value to be "wrapped" again (since you are inside an async function), so it is always redundant.

It does not affect the behavior of your code, which is why your tests still pass.

Edit:

After reading a bit on the no-return-await rule from eslint, turns out there is one case in which it is not redundant, which is inside a try-catch block.

async function foo() {
    try {
        return await bar();
    } catch (error) {}
}

the await is necessary to be able to catch errors thrown from bar() .