JS Practice — Built-in Objects

String.prototype.indexOf() — fromIndex parameter

📖 Usage Example

const str = 'hello world'
str.indexOf('world')    // → 6
str.indexOf('xyz')      // → -1
str.indexOf('l')        // → 2

Use indexOf() to find the index of the first occurrence of a substring, returning -1 if not found.

String.prototype.indexOf() — fromIndex

The optional second argument sets the start position of the search.

Challenge: Implement findAfter(str, sub, from) using .indexOf(sub, from).

findAfter('hello hello', 'hello', 1) // → 6

💡 Hints (1)