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

Example

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();
}

References

• Rule Source