forEach does not support break or continue, each iteration involves a new callback

forEach-break-continue-await.js

(async function () {
  const arr = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];

  // SyntaxError: Illegal break statement
  arr.forEach(n => {
    if (n === 3) {
      break;
    }
    console.log(n);
  });
  
  // SyntaxError: Illegal continue statement: no surrounding iteration statement
  arr.forEach(n => {
    if (n === 3) {
      continue;
    }
    console.log(n);
  });

  // for loop is ok with break
  for (const n of arr) {
    if (n === 3) {
      break;
    }
    console.log(n);
  }
  
  // for loop is ok with continue
  for (const n of arr) {
    if (n === 3) {
      continue;
    }
    console.log(n);
  }
  
  // while is ok with break
  let i = 0;
  while (i < arr.length) {
    if (i === 3) {
      break;
    }
    console.log(arr[i++]);
  }
  
  // while is ok with continue
  let i = 0;
  while (i < arr.length) {
    if (i === 3) {
      i++; // don't forget ++, otherwise the loop never ends
      continue;
    }
    console.log(arr[i++]);
  }
  
  // do while is ok with break
  let i = 0;
  do {
    if (i === 3) {
      break;
    }
    console.log(arr[i++]);
  } while (i < arr.length);

  // do while is ok with continue
  let i = 0;
  do {
    if (i === 3) {
      i++; // don't forget ++, otherwise the loop never ends
      continue;
    }
    console.log(arr[i++]);
  } while (i < arr.length);
  
  
  
  // involves 10 independent async callbacks, one callback will no await for another, so total delay is arround 1s
  arr.forEach(async n => {
    const m = await new Promise(resolve => setTimeout(() => resolve(n * 2), 1000));
    console.log(m);
  });

  // involves only the outter async function, each iteration await for 1s
  for (const n of arr) {
    const m = await new Promise(resolve => setTimeout(() => resolve(n * 2), 1000));
    console.log(m);
  }
})();