使用for循环和if..else语句迭代并检查数组

Question

I am trying to make an array with names, then to iterate them using a for of loop and then to check the iteration using a if else statement. My code is below, but it did not work, I saw no result. I tried with for in, the same bad result. In Html file I have a paraghraph with demo id and a button with function for iterate and checking array

function availableName() {

 const check = document.getElementById('userID');
 const takenNames=['manuel','remus','manuel-remus','tomi','mirel'];
 const reservedNames=['cristina','angela','rusanda','costantin'];
 const givenNames=[...takenNames, ...reservedNames];

  for (givenName of givenNames) {
  if (givenName === check) {
      sayMessage=givenName +"Not available!";
 }
 else {
   sayMessage= givenName +"Available";
 }

 }
document.getElementById("available").innerHTML= sayMessage;
 };

Answer 1

Why not use the function isInArray?

function isInArray(value, array) {
    return array.indexOf(value) > -1;
}

function availableName() {
const check = document.getElementById('userID');
 const takenNames=['manuel','remus','manuel-remus','tomi','mirel'];
 const reservedNames=['cristina','angela','rusanda','costantin'];
 const givenNames=[...takenNames, ...reservedNames];
for (givenName of givenNames) {
  if (isInArray(check, givenNames)) {
      sayMessage=givenName +"Not available!";
 }
 else {
   sayMessage= givenName +"Available";
 }

 }
document.getElementById("available").innerHTML= sayMessage;
 };

Answer 2

First of all you need to get the value of the input using .value as stated in comments.

Then to check its existence in the array you can use one of Array 's built-in methods, such as includes() or indexOf() .

This is how should be your code:

function availableName() {
  const check = document.getElementById('userID').value;
  const takenNames = ['manuel', 'remus', 'manuel-remus', 'tomi', 'mirel'];
  const reservedNames = ['cristina', 'angela', 'rusanda', 'costantin'];
  const givenNames = [...takenNames, ...reservedNames];

  if (givenNames.indexOf(check) > 0) {
    sayMessage = check + " Not available!";
  } else {
    sayMessage = check + " Available";
  }
  document.getElementById("available").innerHTML = sayMessage;
};

Demo:

This is a Demo:

 function availableName() { //const check = document.getElementById('userID').value; const check = "cristina"; const takenNames = ['manuel', 'remus', 'manuel-remus', 'tomi', 'mirel']; const reservedNames = ['cristina', 'angela', 'rusanda', 'costantin']; const givenNames = [...takenNames, ...reservedNames]; if (givenNames.indexOf(check) > 0) { sayMessage = check + " Not available!"; } else { sayMessage = check + " Available"; } document.getElementById("available").innerHTML = sayMessage; }; availableName(); 

 <div id="available"></div>