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Avoid Empty Functions in TypeScript

Medium
intentionalityMaintainabilityclarity

What is it?​

This practice is triggered when functions are defined without any implementation. An empty function can indicate an oversight, incomplete feature, or deceptive code that promises functionality without providing it.

Why apply it?​

Empty functions can be confusing and misleading for developers. They may imply that a certain behavior is implemented when in reality nothing happens. To ensure clear, reliable, and maintainable code, functions should either have a meaningful implementation, throw an explicit error when not supported, or include a comment explaining why the function remains intentionally blank.

How to Fix it?​

Provide the intended functionality within the function body. If the function is not yet implemented or is intentionally left blank (for example, when overriding a method), include an explanatory comment or throw an informative error.

Examples​

Example 1:​

Negative​

Incorrect implementation that violates the practice.

function calculateTotal(prices: number[]): number {
  
  
  
}

Example 2:​

Positive​

Correct implementation following the practice.

function calculateTotal(prices: number[]): number {
  if (prices.length === 0) {
    return 0;
  }
  const total = prices.reduce((sum, price) => sum + price, 0);
  console.log("Total calculated:", total);
  return total;
}

Negative​

Incorrect implementation that violates the practice.

class BaseComponent {
  render(): string {
    return "<div>Base Content</div>";
  }
}

class ChildComponent extends BaseComponent {
  render(): string {
    
    
  }
}

Example 3:​

Positive​

Correct implementation following the practice.

class BaseComponent {
  render(): string {
    return "<div>Base Content</div>";
  }
}

class ChildComponent extends BaseComponent {
  render(): string {
    // Intentionally overriding to maintain parent's behavior.
    // Additional customization might be added later.
    return super.render();
  }
}

Example 4:​

Positive​

Correct implementation following the practice.

function notImplementedFeature(): void {
  throw new Error("notImplementedFeature cannot be executed because it is under development.");
  // Additional debug or logging statements could be added here if needed.
}

Negative​

Incorrect implementation that violates the practice.

function notImplementedFeature(): void {
  
  
  
}