Type Conversion - Part 1

To convert between different data types in JavaScript, we need to use type conversion.

JavaScript supports both implicit and explicit type conversion. Let's focus on the most common explicit conversion methods part 1:

parseInt and parseFloat

// String to Number conversion using parseInt and parseFloat
let str = "42";
let num1 = parseInt(str);    // Converts to integer
let num2 = parseFloat("42.5");  // Converts to floating-point

console.log(num1);  // Outputs: 42
console.log(num2);  // Outputs: 42.5

Both functions read the number from the start of the string and stop at the first character that is not part of a number. If the string does not start with a number, they return NaN (Not a Number):

console.log(parseInt("5ab"));      // Outputs: 5 (parses until invalid character)
console.log(parseFloat("5.2xyz")); // Outputs: 5.2 (parses until invalid character)
console.log(parseFloat("abc123")); // Outputs: NaN (no number at the start)

Values that come from user input (like inp[0]) are always strings, so convert them with parseInt or parseFloat before doing math: otherwise + joins them as text instead of adding them.

It is important to use the right type because it can affect the output.

Concatenating two strings: "5" + "5" == "55"

Adding two numbers: 5 + 5 == 10

Understanding type conversion is essential for writing reliable JavaScript code and avoiding unexpected results in your programs.