Question 33

Question

How would you create a custom symbol registry to prevent collision of Symbol values?

Answer

While the Symbol() function generates unique symbols in most cases, creating a custom symbol registry can be beneficial for specific scenarios where you need finer control and predictability over symbol assignments.

Here's how you could implement a basic custom symbol registry:

class SymbolRegistry {
  constructor() {
    this.symbols = {}; // Map to store registered symbols
  }

  register(name) {
    if (!this.hasSymbol(name)) {
      const symbol = Symbol(name); 
      this.symbols[name] = symbol;
      return symbol;
    } else {
      console.warn(`Symbol '${name}' already exists in the registry`);
      return this.symbols[name];
    }
  }

  hasSymbol(name) {
    return !!this.symbols[name];
  }

  getSymbol(name) {
    return this.symbols[name];
  }
}

// Usage Example:
const registry = new SymbolRegistry();

const mySymbol1 = registry.register('data');
const mySymbol2 = registry.register('view'); 

console.log(mySymbol1); // Output unique symbol for 'data'
console.log(registry.getSymbol('data')); // Accessing the registered symbol

Explanation:

1. SymbolRegistry Class: We create a class to manage our symbols. It has a symbols map to store registered symbols using names as keys.

2. register(name) Method:

   • Checks if a symbol with the given name already exists in the registry.

   • If not, it generates a new symbol using Symbol(name) and stores it in the symbols map, returning the newly created symbol.

3. hasSymbol(name) Method:

   • Checks if a symbol with the given name is present in the registry.

4. getSymbol(name) Method:

   • Returns the previously registered symbol associated with the given name.

Benefits of Using a Symbol Registry:

• Controlled Namespace: Ensures that symbols used within your application are unique and avoid collisions, even across different modules or components.

• Readability and Maintainability: Makes it easier to understand which symbols represent specific concepts in your code.

• Testability: You can easily mock or stub symbol values during testing.