What's the best way to break from nested loops in JavaScript?
What's the best way to break from nested loops in Javascript?
//Write the links to the page.
for (var x = 0; x < Args.length; x++)
{
for (var Heading in Navigation.Headings)
{
for (var Item in Navigation.Headings[Heading])
{
if (Args[x] == Navigation.Headings[Heading][Item].Name)
{
document.write("<a href=\""
+ Navigation.Headings[Heading][Item].URL + "\">"
+ Navigation.Headings[Heading][Item].Name + "</a> : ");
break; // <---HERE, I need to break out of two loops.
}
}
}
}
Just like Perl,
loop1:
for (var i in set1) {
loop2:
for (var j in set2) {
loop3:
for (var k in set3) {
break loop2; // breaks out of loop3 and loop2
}
}
}
as defined in EMCA-262 section 12.12. [MDN Docs]
Unlike C, these labels can only be used for continue
and break
, as Javascript does not have goto
.
Wrap that up in a function and then just return
.
I'm a little late to the party but the following is a language-agnostic approach which doesn't use GOTO/labels or function wrapping:
for (var x = Set1.length; x > 0; x--)
{
for (var y = Set2.length; y > 0; y--)
{
for (var z = Set3.length; z > 0; z--)
{
z = y = -1; // terminates second loop
// z = y = x = -1; // terminate first loop
}
}
}
On the upside it flows naturally which should please the non-GOTO crowd. On the downside, the inner loop needs to complete the current iteration before terminating so it might not be applicable in some scenarios.
I realize this is a really old topic, but since my standard approach is not here yet, I thought I post it for the future googlers.
var a, b, abort = false;
for (a = 0; a < 10 && !abort; a++) {
for (b = 0; b < 10 && !abort; b++) {
if (condition) {
doSomeThing();
abort = true;
}
}
}
Quite simple:
var a = [1, 2, 3];
var b = [4, 5, 6];
var breakCheck1 = false;
for (var i in a) {
for (var j in b) {
breakCheck1 = true;
break;
}
if (breakCheck1) break;
}