Say you have a for loop:

const list = ['a', 'b', 'c']
for (let i = 0; i < list.length; i++) {
  console.log(`${i} ${list[i]}`)
}

If you want to break at some point, say when you reach the element b, you can use the break statement:

const list = ['a', 'b', 'c']
for (let i = 0; i < list.length; i++) {
  console.log(`${i} ${list[i]}`)
  if (list[i] === 'b') {
    break
  }
}

You can use break also to break out of a for..of loop:

const list = ['a', 'b', 'c']

for (const value of list) {
  console.log(value)
  if (value === 'b') {
    break
  }
}

Note: there is no way to break out of a forEach loop, so (if you need to) use either for or for..of.