1. Forward traversal requires i-- to change the subscript (ps: note that the for.. in method cannot control traversal, i-- is invalid)
for (let i = 0; i < arr.length; i++) {
if (arr[i] === 5) {
arr.splice(i, 1); // Will move the following elements forward in sequence and reduce the array length by 1
i--; // If not subtracted, one element will be missed.
}
}
2. Flashback traversal. No matter how many elements are deleted during flashback traversal, the elements that have not been traversed will not be skipped.
for (let i = arr.length - 1; i >= 0; i--) {
if (arr[i] === 5) { arr.splice(i, 1); }
}
3. Filter out a new array and reassign the value
arr = arr.filter(item => item !== 5);