iife and crockford-iife functions break about async-to-gen HOT 5 CLOSED

Thank you for your explain.

from async-to-gen.

Could you provide more info about what you expect to happen and what you see instead?

When I run your first example in async-node

// iife
(async () => {
  await test()
})()

I get the correct output of a Promise.

Your second example is not legal syntax for the same reason that the following is not legal syntax:

(() => {
  test()
}())

Crockford style iifes only work with function expressions, not arrow functions, and async functions work in this style as well in async-node. This example returns a Promise:

(async function () {
  test()
}())

from async-to-gen.

Added these two IIFE to the test cases to illustrate that they transform as expected

from async-to-gen.

Below case breaks:

const test = {
  async run () {
  }
}

(async () => {
  await test.run()
})()

error:

iife.js:6
(() => __async(function*(){
^

TypeError: (intermediate value) is not a function

from async-to-gen.

That error is expected given that code (though node could be more helpful with its errors).

You can test this by trying the same thing using node without the async/await (not using this library at all):

const test = {
  run () {
  }
}

(() => {
  test.run()
})()

iife.js:6
(() => {
^

TypeError: (intermediate value) is not a function

This is because of Automatic Semicolon Insertion (a good resource: https://github.com/getify/You-Dont-Know-JS/blob/master/types%20%26%20grammar/ch5.md#automatic-semicolons)

This is because any expression followed by () assumes that you mean the previous expression is a function to be called. In this case: const test = {run(){}}(()=>{test.run()}) JavaScript thinks test will be assigned the result of a function call where {run(){}} is the "intermediate value" function to call and ()=>{test.run()} is the argument to the function.

Check out https://astexplorer.net/#/efPw48Ufoh to see how JavaScript parses this.

The fix is to ensure there's a semicolon somewhere before your IIFE.

from async-to-gen.