break statement
break
statement terminates the execution of the immediate surrounding loop.
break;
or
break [label];
where
break
is keyword.label
is optional identifier of a loop.
Examples
1. break for loop if i
is 5
.
for (let i = 0; i < 20; i++) {
if (i == 5) {
break;
}
console.log('hello world');
}
2. break while loop if i
is 5
.
let i = 0;
while (i < 20) {
if (i == 5) {
break;
}
console.log('hello world');
i++;
}
3. break nested loop
for (let row = 0; row < 4; row++) {
for (let column = 0; column < 4; column++) {
if (column > row) {
break;
}
console.log(row + "-" + column);
}
}
If column > row
, inner for loop breaks, because inner for loop is the immediate loop surrounding the break statement.
4. break labeled loop
a: for (let row = 0; row < 4; row++) {
for (let column = 0; column < 4; column++) {
if (column > row) {
break a;
}
console.log(row + "-" + column);
}
}
a
is the label given to outer for loop. if column > row
, we are breaking the loop labeled with a
.