rspec/rules/S1439/javascript/rule.adoc

== Why is this an issue?

Labels allow specifying a target statement to jump to using the `break` or `continue` statements. It's possible to assign a label to any statement or block of statements. However, using it with any statement can create a complex control flow path, making the code harder to understand and maintain.

[source,javascript,diff-id=1,diff-type=noncompliant]
----
myLabel: if (i % 2 == 0) { // Noncompliant: Labeling an if statement
  if (i == 12) {
    console.log("12");
    break myLabel;
  }
  console.log("Even number, but not 12");
}
----

Instead of using a label with these nested `if` statements, this code block should be refactored.

[source,javascript,diff-id=1,diff-type=compliant]
----
if (i % 2 == 0) { // Compliant
  if (i == 12) {
    console.log("12");
  } else {
    console.log("Even number, but not 12");
  }
}
----

The rule considers that `while`, `do-while`, `for`, and `switch` statements don't create complex control flow paths, thus these statements are not reported.

[source,javascript]
----
outerLoop: for (let i = 0; i < 10; i++) { // Compliant
  for (let j = 0; j < 10; j++) {
    if (condition(i, j)) {
      break outerLoop;
    }
  }
}
----


== Resources

=== Documentation

- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/label[MDN - label]

=== Related rules

- S1119 - Labels should not be used


ifdef::env-github,rspecator-view[]

'''
== Implementation Specification
(visible only on this page)

include::../message.adoc[]

'''
== Comments And Links
(visible only on this page)

include::../comments-and-links.adoc[]

endif::env-github,rspecator-view[]