JS Practice — Built-in Objects

String.prototype.includes() — case-sensitive

📖 Usage Example

const str = 'Hello, World!'
str.includes('World')    // → true
str.includes('xyz')      // → false
str.includes('Hello', 1) // → false

Use includes() to check if a string contains a specific substring, with an optional start position.

String.prototype.includes() — Case Sensitivity

.includes() is case-sensitive.

Challenge: Implement includesIgnoreCase(str, sub) that checks for sub case-insensitively.

includesIgnoreCase('Hello World', 'hello') // → true

💡 Hints (1)