javascriptarraysdom

In Javascript, why is [somevar] considered an array?

In Javascript, the following declaration is from a text input:

numberInput = document.getElementById('number-input');

In HTML, "number-input" is this:

<input type="number" id="number-input" />

The numberInput variable is passed to a function like this:

function processInputs(list) 
  let total = 0;
  // add the items in list to a total
  for (const item of list) {
    total += item;
  }

Why does the statement processInputs([numberInput]) treat numberInput as an Array/NodeLIst ?

Solution

  • The code you are presenting is wrong...

    at a minima it should be:

    const numberInput = document.getElementById('number-input');
// "const" is missing in your code


function processInputs(list)
  {                           // "{" is missing in your code
  let total = 0;
  // add the items in list to a total
  for (const item of list)
    { 
    total += item.valueAsNumber;  // ".valueAsNumber" is missing in your code
    }  
  console.log( total );    // added for showing result
  }

processInputs( [numberInput] );

/* same as :

let fct_Argument = [numberInput];
console.log( typeof fct_Argument );  // ---> Array

processInputs( fct_Argument );

*/
    <input type="number" id="number-input" value="50" />