how to exit from a function without return in JavaScript?

Question

I have this function

function deleteItem() {
   deleteInvItems({
        where: {
            invoice_id: invData.invNo,
            [Op.not]: [{
                item_id: itemIDs
            }]
        }
    }).then(resp => {      
        if (!resp) return false;
    });
    
    deleteInvSumItems([{
        where: {
            invoice_id: invData.invNo,              
            [Op.not]: [{
                hsn_code: invUniqueHsnCodes
            }]
        }
    }]).then(resp => {      
        if (!resp) return false;
    });
    
    return true;
}

I want to exit the function with return false; if I get false response from server.

But if I call inner functions without return keyword unlike return deleteInvItems({...}) and return deleteInvSumItems({...}). I'm not able to exit the parent function.

How can I exit the parent function deleteItem() with retuning false if I get false response from server?

[How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321) — adiga, Apr 24 '21 at 08:56
Where does ```resp``` come from and what do you mean with exit the parent function? What happens - infinite loop or an error? — biberman, Apr 24 '21 at 09:20
Are you looking to only run deleteInvSumItems if deleteInvItems doesn't fail? i.e. is the purpose of the `if (!resp) return false;` in the then() callback of deleteInvItems to stop deleteInvSumItems from running? — Ben Stephens, Apr 24 '21 at 09:33

score 1 · Accepted Answer · answered Apr 24 '21 at 09:24

You might want to use the async/await syntax instead of Promise.then(...).

async function deleteItem() {
  try {
    const response = await deleteInvSumItems(...)    // pass parameters here
    if(!response) {
      // since this is not part of an inner callback function
      // it will exit the deleteItem function
      return       
     }
   } catch (err) {
     // handle error
   }

Note: async/await is supported since ECMAScript 2017, so make sure your platform where you run your code supports it.

score 0 · Answer 2 · answered Apr 24 '21 at 09:25

Your function needs to be async:

async function deleteItem() {
   const res = await deleteInvItems({
        where: {
            invoice_id: invData.invNo,
            [Op.not]: [{
                item_id: itemIDs
            }]
        }
    })
// do something with res
}

score 0 · Answer 3 · answered Apr 24 '21 at 09:27

Since your code is asynchronous, you can't "just" exit the function.

You have to work with Promise, or with Async/Await.

If you choose to work with promises, just return the promise, and use then.

I think that since your code needs to stop the then chain with 2 promises (deleteInvItems and deleteInvSumItems), it's easier and readable to use async await here:

//when you call the function, use await to get the result:
let finalResult = await deleteItem();

async function deleteItem() {
  let val1 = await deleteInvItems({
    where: {
      invoice_id: invData.invNo,
      [Op.not]: [{
        item_id: itemIDs
      }]
    }
  }).then(resp => {
    if (!resp) return false;
  });
  let val2 = await deleteInvSumItems([{
    where: {
      invoice_id: invData.invNo,
      [Op.not]: [{
        hsn_code: invUniqueHsnCodes
      }]
    }
  }]).then(resp => {
    if (!resp) return false;
  });

  return val1 && val2;
}

score -1 · Answer 4 · answered Apr 24 '21 at 09:19

Use the break statement with a label reference, to "jump out" of a nested for loop:

 let text = "";
 let i;
     mainLoop:
   for (let k = 0; k < 5; k++) {
     for (i = 0; i < 5; i++) {
       if (i === 3) {
         break mainLoop;
       }
       text += "The number is " + i + "<br>";
     }
   }
 document.getElementById("demo").innerHTML = text;

<p id="demo"></p>

score -3 · Answer 5 · edited Apr 24 '21 at 09:44

-3

You can use break method for exiting in a function in js . for eg :

const getName = () => {
  getName: {
    console.log("I get logged");

    break getName;

    //exits the function

    console.log("I don't get logged");
  }
};

edited Apr 24 '21 at 09:44

adiga

34,372
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answered Apr 24 '21 at 09:05

Coder - Krishna

3

how to exit from a function without return in JavaScript?

5 Answers5