unnecessaryBooleanCasts

Reports unnecessary boolean casts.

✅ This rule is included in the ts logical presets.

Boolean contexts such as if and while statements evaluate values for falsiness or truthiness. Using !!value or Boolean(value) in those contexts is redundant because that doesn’t change whether the value is falsy or truthy.

This rule reports on boolean casts in already-boolean contexts.

Examples

❌ Incorrect

if (!!value) {
  // ...
}

while (Boolean(condition)) {
  // ...
}

✅ Correct

if (value) {
  // ...
}

while (condition) {
  // ...
}

Options

This rule is not configurable.

When Not To Use It

If you prefer explicit boolean casts for clarity, this rule may not be for you.

Further Reading

• MDN: Boolean
• MDN: Logical NOT

Equivalents in Other Linters

• Biome: noExtraBooleanCast
• Deno: no-extra-boolean-cast
• ESLint: no-extra-boolean-cast
• Oxlint: eslint/no-extra-boolean-cast