What command I must use, to get out of the for loop, also from //code inside jump direct to //code after
//code before
for(var a in b)
{
switch(something)
{
case something:
{
//code inside
break;
}
}
}
//code after
You can use label. Have a labeled statement and break to that label. outerLoop is the label I have used here.
//code before
outerLoop:
for (var a in b) {
switch (something) {
case 'case1':
//code inside
break outerLoop;
}
}
//code after
use another variable to flag when you need to exit:
var b = { firstName: 'Peter', lastName: 'Smith' };
var keepGoing = true;
for (var a in b) {
switch (true) {
case 1:
keepGoing = false;
break;
}
if (!keepGoing) break;
console.log('switch end');
}
console.log('for end');
break permits a label parameter, I personally think labels went out with BASIC and just lead to spaghetti code...)Unfortunately, Javascript doesn't have allow breaking through multiple levels. The easiest way to do this is to leverage the power of the return statement by creating an anonymous function:
//code before
(function () {
for (var a in b) {
switch (something) {
case something:
{
//code inside
return;
}
}
}
}());
//code after
This works because return leaves the function and therefore implicitly leaves the loop, moving you straight to code after
As pointed out in the comments, my above answer is incorrect and it is possible to multi-level breaking, as in Chubby Boy's answer, which I have upvoted.
Whether this is wise is, from a seven-year-later perspective, somewhat questionable.
return and not associate it with the anonymous function (making maintenance a little more confusing later). Now, granted, this is not a complex piece of code, but applying this in practice throughout could become ugly fast.
it depends on what you want to accomplish... one thing I commonly do is something like this:
//code before
for(var a in b)
{
var breakFor = false;
switch(something)
{
case something:
{
//code inside
breakFor = true;
break;
}
}
if (breakFor)
break;
}
//code after
You can tell which loop / switch to break.
function foo ()
{
dance:
for(var k = 0; k < 4; k++){
for(var m = 0; m < 4; m++){
if(m == 2){
break dance;
}
}
}
}
See this answer.
for(var i=0; i<b.length; i++) {
switch (something) {
case 'something1':
i=b.length;
}
}
When the iteration variable i reaches the end of the loop, it breaks. But one can force the iteration variable to reach the end of the loop.
i=b.length. Moreover, it's very dangerous if i is set lower than b.length, that will run forever!!!. So I recommend we should use function, label or flag instead of this.
b < length, not <=, so once you set i = b.length, the condition will fail. The loop will not run one more time. In fact, even if you change it to i = b.length - 1, it will still break after this loop, because the incrementor runs before the condition.I always find using conditional statements one of the easiest ways to control the code flow, at least conceptually.
var done = false;
//code before for loop
for(var a in b){
switch(switchParameter){
case firstCase:
//code inside
done = true;
break;
}
}
if(done)
break;
}
//code outside of for loop
const array = [1, 2, 3, 4, 5];
outerLoop: for (let i = 0; i < array.length; i++) {
switch (array[i]) {
case 1:
console.log('Case 1');
break; // This breaks out of the switch statement
case 2:
console.log('Case 2');
break; // This breaks out of the switch statement
case 3:
console.log('Case 3');
break outerLoop; // This breaks out of both the switch and the for loop
default:
console.log('Default case');
}
}
console.log('Loop exited');
break;right after the closing}of the switch statement.