When One Becomes Another

In JS, types can change automatically, often in the most unexpected ways.

1. To String (String Conversion)

Happens when we need a text representation.

let value = true;
alert(String(value)); // "true"

2. To Number (Numeric Conversion)

Happens in mathematical expressions.

alert( "6" / "2" ); // 3, strings became numbers automatically!

Explicit conversion: Number(str). Special cases:

• undefined → NaN
• null → 0
• true / false → 1 / 0
• " 123 " → 123 (spaces at the edges are removed)

3. To Boolean (Boolean Conversion)

The most common conversion type.

• ** " Falsy " values:** 0, "", null, undefined, NaN. They always turn into false.
• Everything else: true.