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
nullor 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!
