Loops

For

For loops go from a start position to an end position of an interable object.

for (let i = 0; i < array.length; i++) {
  console.log(array[i]);
}

Break

While inside a for loop if you use the break syntax then the execution will skip to outside the for loop.

Continue

While inside a for loop if you use the continue syntax then the execution will just to the next iteration in the loop.

While

A while loop will execute until the condition is false.

while (age < 50) {
  console.log(age);
  age++;
}

Do...while

A do...while loop will execute until the while condition is false. The difference from a while loop is that it will execute at least once, as the condition check only happens at the end of each execution.

For...of

A for...of loop will iterate through an iterable object. It is cleaner than using a standard for loop as long as you don't need to know the index position.

const people = ["James", "Rita", "Mel"];
for (const name of people) {
  console.log(name);
}

For...in

A for...in loop is used for iterating over an object. The value for each loop is the property key.

const items = { a: 1, b: 2, c: 3 };
for (const item in items) {
  console.log(item, items[item]);
}

This will output; a 1 b 2 c 3