JavaScript - for statement

In this article, we would like to show you for statement to create loops in JavaScript.

Syntax

for ([initial-expression]; [condition-expression]; [final-expression]) {
   // statement
}

Note:

All three expressions in the head of the for loop are optional (initial-expression, condition-expression and final-expression). For more details see the examples below.

Practical examples

Example 1

In this example, we declare i variable and initialize it with 0. the for statement checks if i is less than 3, performs the statement inside the braces and increments i by 1 after each pass through the loop.

// ONLINE-RUNNER:browser;

for (let i = 0; i < 3; ++i) {
  console.log(i);
}

Example 2

In this example, we skip the initial-expression in the head of the for loop.

// ONLINE-RUNNER:browser;

let i = 0

for (; i < 3; ++i) {
  console.log(i);
}

Example 3

In this example, we omit the condition-expression.

// ONLINE-RUNNER:browser;

for (let i = 0; ; i++) {
  console.log(i);
  if (i > 3) break;
}

Example 4

In this example, we omit all three blocks.

// ONLINE-RUNNER:browser;

let i = 0;

for (;;) {
  if (i > 3) break;
  console.log(i);
  i++;
}

References

1. for - JavaScript | MDN