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eslint/no-constant-condition Correctness

✅ This rule is turned on by default.

What it does

Disallow constant expressions in conditions.

Why is this bad?

A constant expression (for example, a literal) as a test condition might be a typo or development trigger for a specific behavior.

This rule disallows constant expressions in the test condition of:

• if, for, while, or do...while statement
• ?: ternary expression

Examples

Examples of incorrect code for this rule:

if (false) {
  doSomethingUnfinished();
}

if (new Boolean(x)) {
  doSomethingAlways();
}
if ((x ||= true)) {
  doSomethingAlways();
}

do {
  doSomethingForever();
} while ((x = -1));

Examples of correct code for this rule:

if (x === 0) {
  doSomething();
}

while (typeof x === "undefined") {
  doSomething();
}

Configuration

This rule accepts a configuration object with the following properties:

checkLoops

type: boolean | "all" | "allExceptWhileTrue" | "none"

How to use

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

Config (.oxlintrc.json)

{
  "rules": {
    "no-constant-condition": "error"
  }
}

Config (oxlint.config.ts)

import { defineConfig } from "oxlint";

export default defineConfig({
  rules: {
    "no-constant-condition": "error",
  },
});

CLI

oxlint --deny no-constant-condition

Version

This rule was added in v0.0.3.

References

• Rule Source
• Upstream rule docs
• Open rule in Oxc Playground