unnecessaryBlocks

Reports standalone block statements that don't create a meaningful scope.

✅ This rule is included in the ts stylistic preset.

Standalone block statements that aren’t part of control flow structures (if/else, loops, switch, etc.) or don’t create a meaningful lexical scope can make code harder to understand. In modern JavaScript and TypeScript, blocks primarily serve to create lexical scope for let and const variables, but using standalone blocks for this purpose is often confusing compared to other patterns like functions or modules.

Examples

❌ Incorrect

{
  const temporaryValue = computeValue();
  processValue(temporaryValue);
}

function processData() {
  {
    const result = calculate();
    console.log(result);
  }
}

✅ Correct

const temporaryValue = computeValue();
processValue(temporaryValue);

function processData() {
  const result = calculate();
  console.log(result);
}

// Valid: block is part of control flow
if (condition) {
  const value = getValue();
  processValue(value);
}

// Valid: block creates scope in switch case
switch (type) {
  case "a": {
    const value = getA();
    break;
  }
}

Options

This rule is not configurable.

When Not To Use It

If you frequently use standalone blocks for visual organization or temporary scoping in ways that your team finds helpful, you might choose to disable this rule. However, consider whether extracting to functions or using other scoping mechanisms would be clearer.

Further Reading

• MDN: Block statements
• MDN: let and const scoping

Equivalents in Other Linters

• Biome: noUselessLoneBlockStatements
• ESLint: no-lone-blocks
• Oxlint: eslint/no-lone-blocks