Lecture 7: Built-in Functions in JavaScript

1. String Methods

• split(separator): Splits a string into an array of substrings based on a specified separator.
• charAt(index): Returns the character located at the specified index.
• toUpperCase(): Converts all characters in a string to uppercase.
• slice(start, end): Extracts a portion of a string and returns it as a new string.

2. Array Methods

• map(callback): Applies a function to each element of an array, creating a new array with the results.
  • Example: Doubling numbers in an array.

3. Math Methods

• Math.pow(base, exponent): Calculates the value of a base raised to the power of an exponent.
• Math.sqrt(number): Returns the square root of a given number.

4. Practical Logic Examples

• Circle Area: Calculated using the formula $\pi \times r^2$ using Math.pow(radius, 2).
• Capitalizing Words: Involves splitting a sentence, using map to target the first character with charAt(0).toUpperCase(), and joining the results back together.