eslint/no-labels Style

What it does

Disallow labeled statements.

Why is this bad?

Labeled statements in JavaScript are used in conjunction with break and continue to control flow around multiple loops. For example:

outer:
while (true) {
  while (true) {
    break outer;
  }
}

The break outer statement ensures that this code will not result in an infinite loop because control is returned to the next statement after the outer label was applied. If this statement was changed to be just break, control would flow back to the outer while statement and an infinite loop would result. While convenient in some cases, labels tend to be used only rarely and are frowned upon by some as a remedial form of flow control that is more error prone and harder to understand.

Examples

Examples of incorrect code for this rule:

label:
while (true) {
  // ...
}

label:
while (true) {
  break label;
}

label:
while (true) {
  continue label;
}

label:
switch (a) {
  case 0:
    break label;
}

label:
{
  break label;
}

label:
if (a) {
  break label;
}

Examples of correct code for this rule:

var f = {
  label: "foo",
};

while (true) {
  break;
}

while (true) {
  continue;
}

Configuration

This rule accepts a configuration object with the following properties:

allowLoop

type: boolean

default: false

If set to true, this rule ignores labels which are sticking to loop statements. Examples of correct code with this option set to true:

label:
while (true) {
  break label;
}

allowSwitch

type: boolean

default: false

If set to true, this rule ignores labels which are sticking to switch statements. Examples of correct code with this option set to true:

label:
switch (a) {
  case 0:
    break label;
}

How to use

To enable this rule in the CLI or using the config file, you can use:

CLI

oxlint --deny no-labels

Config (.oxlintrc.json)

{
  "rules": {
    "no-labels": "error"
  }
}

References

• Rule Source