JS Arrow fuinction returns self not function-CodePudding

In React I'm using utility functions to handle the api calls. When the Arrow function is no longer anonymous it returns a pending promise, which is what I would like. However when the arrow function is anonymous it returns the function.

Is there any way to return a pending promise in one line?

Here is what the function looks like when not anonymous:

const list = () => {
    let res = async () => await api.get("list");
    return res();
}

Here is what it looks like anonymous:

const list = () => {
    return async () => await api.get("list")
}

CodePudding user response：

Because you're just returning the function, not executing it. This executes the function:

res();

Nowhere in the second example do you have that additional set of parentheses to execute it. Add them:

const list = () => {
  return (async () => await api.get("list"))();
}

Or, even simpler, don't wrap the operation in an unnecessary function in the first place:

const list = () => {
  return api.get("list");
}

CodePudding user response：

With your second example you are returning a function, not the result of the function. Store the function in an object and call the function:

const list = () => {
    return (async () => await api.get("list"))();
}

CodePudding user response：

You are returning the function res in the second case, not the output of res. You can use an IIFE to return the value of res as wanted:

const list = () => {
    return api.get("list")
}