How to parse string to boolean in Typescript?

In TypeScript, parsing a string to a boolean typically involves converting specific string values (e.g., "true" or "false") to their corresponding boolean values. Here’s how you can do it:

Example 1: Basic Parsing

const parseBoolean = (value: string): boolean => {
  return value.toLowerCase() === "true";
};

// Usage
console.log(parseBoolean("true")); // Output: true
console.log(parseBoolean("false")); // Output: false
console.log(parseBoolean("TRUE")); // Output: true

Example 2: Safer Parsing with Validation

To handle invalid values gracefully:

const parseBooleanSafe = (value: string): boolean | null => {
  const lowerValue = value.toLowerCase();
  if (lowerValue === "true") return true;
  if (lowerValue === "false") return false;
  return null; // Return null for invalid input
};

// Usage
console.log(parseBooleanSafe("true")); // Output: true
console.log(parseBooleanSafe("false")); // Output: false
console.log(parseBooleanSafe("not-boolean")); // Output: null

Notes:

toLowerCase() ensures case insensitivity.
Returning null or throwing an error for invalid input is a good practice to avoid unexpected behavior.
If the string isn’t strictly "true" or "false", it won’t match a boolean value.

Choose the approach that aligns with your application’s needs!