Returning array values, not the array iterator in Javascript

Question

How can I return the values of an array? The methods .values() and .entries() seem to return an Array Iterator. This is not what I want. I am also not allowed to modify func1() function for this edge case.

const test = func1();

console.log(test); // actual: [[1,2]] what I want: [1,2]

function func1() { // not allowed to modify func1
  return [func2()];
}

function func2() {
  const set = new Set();
  set.add(1);
  set.add(2);
  return Array.from(set); 
  // return Array.from(set).values() returns Array Iterator
}

Thanks!

in my use case the return value from func2 is not always an array. therefore, I want to see if its possible to just return the values. — robtot
– robtot, Commented May 1, 2021 at 11:32
But func1 always returns an array, so it doesn't matter what func2 returns. — Emiel Zuurbier
– Emiel Zuurbier, Commented May 1, 2021 at 11:36

Sebastian Richner · Accepted Answer · 2021-05-01 11:44:40Z

1

As Bergi stated, func1() will always return an array, no matter what func2() returns. But there are a couple of ways to achieve this based on the return value of func1().

You can either simply use the first element in the array test[0], you can use the Array.flat() method, or the spread operator. See the snippet below.

const test = func1();

function func1() { // not allowed to modify func1
  return [func2()];
}

function func2() {
  const set = new Set();
  set.add(1);
  set.add(2);
  return Array.from(set); 
  // return Array.from(set).values() returns Array Iterator
}

// First element in array
console.log(test[0]);

// Array.flat()
console.log(test.flat());

// Spread operator
console.log(...test);

edited May 1, 2021 at 11:44

answered May 1, 2021 at 11:33

Sebastian Richner

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3 Comments

Bergi Over a year ago

When the OP writes "I am also not allowed to modify func1() function", I doubt they want to modify the console.log call either.

robtot Over a year ago

This reply made me realize all options. Thanks.

Sebastian Richner Over a year ago

@Bergi, you are right, it might not be ideal, but as you correctly stated, there is no other way if OP can't modify func1(), as it will always return an array. I will update my answer accordingly.

Bergi · Accepted Answer · 2021-05-01 11:32:54Z

1

This is not possible. func1() always returns an array with one element, it can never return [1,2], not matter what func2 does. You must modify its code.

answered May 1, 2021 at 11:32

Bergi

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