Web Programming I

for...of

This YouTube video was created by Steve Griffith.

The for...of statementopen in new window is specifically designed to iterate over iterable objects, like strings and arrays, but does not work on object literals. Unlike the for statement, the for...of statement does not rely on an index to retrieve a value but instead stores each value to a defined variable.

With Arrays

The expression of the for...of statement starts with an initialization of the variable used to hold each item's value. This is followed by the keyword of and ends with the iterable.

const animals = ['cat', 'dog', 'mouse']

for (const animal of animals) {
  // Logs all the animals in the array
  console.log(animal) 
}

const incomes = [62000, 67000, 75000]
let total = 0

for (const income of incomes) {
  total += income
}

console.log(total) // 204000

With Strings

The for...of statement also works with strings. When iterating over a string, the defined variable will be assigned to each character, one at a time.

const name = 'Ted Mosby'

for (const char of name) {
  // Logs each character of the name
  console.log(char)
}