Question 198894 in Javascript Question posted in
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Javascript – Passing return value as function arguments (tuple)

I’m trying to use the return value of my function as arguments for my function, however the fact that it’s a tuple is being problematic. This is further compounded by the fact that it will not always be a tuple.

function foo(initial_state, indexer = 0) {
// does something

return [initial_state, indexer + 1];
}

I want to be able to sometimes use the function as simply

foo(initial_state);

but also I want to call the function with the return, as such..

foo(foo());

Instead of the desired behavior, the tuple is put into initial_state, whereas I would want it deconstructed to match the arguments in the function.

I can obviously do a temporary variable like

let some_state, some_index = foo();
foo(some_state, some_index);

But that seems very ugly. There has to be a better way.

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2

Answers


  1. 0

    Use the rest parameters:

    function foo(initial_state, indexer = 0) {
  return [initial_state, indexer + 1];
}

console.log(foo(...foo(0, 0)));
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  2. 0

    You can’t create temporary variable like that as well actually no. That way, only some_index will be assigned to foo()s return value. some_state will be undefined.

    But you can just spread the array to another function.

    foo(...foo(state, indexer))
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