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JavaScript BigInt

BigInt is a special numeric type that allows you to represent integers of arbitrary length. It is useful for handling values too large to fit into a standard JavaScript Number.

Key Topics

Creating BigInt

Append n to the end of an integer or use the BigInt() function to create a BigInt value.

let bigNum = 123456789012345678901234567890n;
console.log(typeof bigNum);

Output

> bigint

Explanation: Using n at the end of the number creates a BigInt, and typeof confirms its type as "bigint".

Operations with BigInt

You can perform arithmetic operations on BigInt values, similar to regular numbers, but both operands must be BigInt.

let a = 1000000000000000000n;
let b = 2n;
console.log(a * b);

Output

> 2000000000000000000n

Explanation: Multiplying two BigInts produces a BigInt result without losing precision.

Mixing BigInt and Number

You cannot mix BigInt and regular Number in arithmetic operations. Convert one type to the other if necessary.

let big = 10n;
let num = 5;
// console.log(big + num); // Error
console.log(big + BigInt(num));

Output

> 15n

Explanation: Converting num to a BigInt with BigInt(num) allows the addition operation without error.

JavaScript Usage in DOM

This DOM-based example demonstrates using BigInt to handle large values and display them on the webpage.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>BigInt in DOM</title>
</head>
<body>
    <h1>BigInt Demo</h1>
    <button onclick="showBigInt()">Show Big Number</button>
    <p id="info"></p>

    <script>
        function showBigInt() {
            let largeValue = 9999999999999999999999999999n;
            document.getElementById("info").textContent = "Large Value: " + largeValue;
        }
    </script>
</body>
</html>

Key Takeaways

  • BigInt: Represent integers beyond Number's safe range.
  • Arithmetic: Perform precise math on very large integers.
  • Type Conversion: Convert between Number and BigInt before mixing.
  • DOM Usage: Display large integer values on webpages without loss of precision.
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