Data type conversion means changing a value from one type to another.

👉 There are two types of conversion:

1. Implicit Conversion (Type Coercion)
2. Explicit Conversion (Type Casting)

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🔹 1. Implicit Conversion (Automatic)

JavaScript automatically converts types when needed.

✅ Example 1: String + Number

let result = "5" + 2;
console.log(result); // "52"

👉 Number 2 is converted to string.

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✅ Example 2: Number – String

let result = "5" - 2;
console.log(result); // 3

👉 String "5" is converted to number.

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✅ Example 3: Boolean Conversion

let result = true + 1;
console.log(result); // 2

👉 true → 1, false → 0

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✅ Example 4: Null Conversion

let result = null + 5;
console.log(result); // 5

👉 null behaves like 0

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⚠️ Strange Cases

console.log("5" * "2"); // 10
console.log("hello" * 2); // NaN

👉 "hello" cannot be converted → NaN (Not a Number)

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🔹 2. Explicit Conversion (Manual)

You manually convert using JavaScript functions.

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✅ Convert to Number

Using Number()

Number("123");    // 123
Number("abc");    // NaN
Number(true);     // 1
Number(false);    // 0

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Using parseInt() and parseFloat()

parseInt("10.5");   // 10
parseFloat("10.5"); // 10.5

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✅ Convert to String

Using String()

String(123);      // "123"
String(true);     // "true"

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Using .toString()

let num = 100;
num.toString();   // "100"

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✅ Convert to Boolean

Using Boolean()

Boolean(1);        // true
Boolean(0);        // false
Boolean("");       // false
Boolean("Hello");  // true
Boolean(null);     // false
Boolean(undefined);// false

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🔹 Truthy vs Falsy Values

❌ Falsy Values:

• 0
• "" (empty string)
• null
• undefined
• NaN
• false

✅ Truthy Values:

Everything else is true

Boolean("Hi"); // true
Boolean(100);  // true

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🔹 Comparison with Type Coercion

== (Loose Equality)

console.log("5" == 5); // true

👉 Converts types before comparison

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=== (Strict Equality)

console.log("5" === 5); // false

👉 No conversion → safer

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🧠 Quick Summary

Conversion Type	Example	Result
Implicit	"5" + 2	"52"
Implicit	"5" - 2	3
Explicit	Number("10")	10
Explicit	String(10)	"10"
Explicit	Boolean(0)	false