BigInt
BigInt is a built-in object in JavaScript that provides a way to represent whole numbers larger than $2^{53} - 1$, which is the largest number JavaScript can reliably represent with the Number primitive.
1. Creating BigInts
You can create a BigInt by appending n to the end of an integer literal or by calling the BigInt() function.
const theBiggestInt = 9007199254740991n;
const alsoHuge = BigInt(9007199254740991);
// ↪ 9007199254740991n
const hugeString = BigInt("9007199254740991");
// ↪ 9007199254740991n2. Why do we need it?
The Number type in JavaScript is a double-precision float. It has a "safe integer" limit (Number.MAX_SAFE_INTEGER). Beyond this limit, calculations become imprecise.
const max = Number.MAX_SAFE_INTEGER; // 9007199254740991
console.log(max + 1); // 9007199254740992 (Correct)
console.log(max + 2); // 9007199254740992 (Wrong! Should be ...93)With BigInt, precision is preserved:
const maxBig = 9007199254740991n;
console.log(maxBig + 2n); // 9007199254740993n (Correct)3. Operations
You can use standard operators (+, *, -, **, %) with BigInts.
const huge = 10n;
console.log(huge + 10n); // 20n
console.log(huge * 2n); // 20n
console.log(huge / 2n); // 5nNote on Division: Since BigInts are integers, division rounds towards zero (truncates the decimal part).
console.log(5n / 2n); // 2n (not 2.5n)4. Mixing Types
You cannot mix BigInt and other types in standard operations. You must perform explicit conversion.
const bigint = 1n;
const number = 2;
// console.log(bigint + number); // TypeError: Cannot mix BigInt and other types
console.log(Number(bigint) + number); // 3
console.log(bigint + BigInt(number)); // 3n5. Comparisons
- Strict Equality (
===):0n === 0isfalse(different types). - Loose Equality (
==):0n == 0istrue. - Relational (
<,>): Works as expected across types.1n < 2istrue.
programming/javascript/vanilla/javascript programming/javascript/vanilla/data-types