For loop

1 minute read

Classic for loop

All three “initialization/test/update” parts used.

for (let j = 4; j < 10; j++) {
  console.log(j);
}
  

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Basic for loop

No initialization or update parts; only the test condition in the middle part (between the two semi-colons (;)).

let i = 1;

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

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For loop that only exits with break or return

This for loop will continuously “spin” unless it reaches a break or return statement, usually based on some condition to wait on that’s easier to specify in the loop body. Shown for completeness, but avoid doing this in normal code.

for (;;) {
  console.log("loop");
  break;
}
  

loop

For loop with continue

This for loop will conditionally continue to the next iteration of the loop, bypassing any remaining statements in the loop body.

for (let n = 0; n <= 5; n++) {
  if (n % 2 == 0) continue;
  console.log(n);
}
  

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