I think I missed something

1

Why do sometimes we need parenthesis for a function call, and sometimes we don’t?

Example:
store.dispatch(loginAction());
vs
store.dispatch(loginAction);

Somewhere I made the assumption that if it didn’t have any args passed or expect any parameters, then it didn’t need the parenthesis when called.

2

You always need parentheses to call a function (ie evaluate it)

The second one is just a reference to the function itself, the function is not being evaluated, it will be called at some later point in the program.

function add(a,b) {
  return a + b;
}

// Call the function 
add(1,2)

// Vs just assigning it to a variable to
// be used later
const example = add;

// ...later
// Call the function
example(1, 2)

This is not a correct assumption; the parentheses are not optional, without them it’s just a variable same as any other variable.

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3

Thank you very much for the thorough explanation.

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