// Extracts the first n digits from a BigInt.
// Converting the BigInt to a string is the most direct and efficient way
// to access its digits without performing repeated arithmetic operations.
function firstNDigits(value: bigint, n: number): string {
// Convert the BigInt to its decimal string representation.
const s: string = value.toString();
// If n exceeds the number of digits, return the whole number.
if (n >= s.length) {
return s;
}
// Return the first n characters (digits).
const result: string = s.slice(0, n);
return result;
}
function main(): void {
// Define a very large BigInt using the BigInt literal syntax.
const bigNumber: bigint = 9876543210987654321098765432109876543210n;
// Choose how many digits to extract.
const n: number = 19;
// Extract the first n digits.
const result: string = firstNDigits(bigNumber, n);
// Display the result.
console.log(`First ${n} digits: ${result}`);
}
main();
/*
run:
First 19 digits: 9876543210987654321
*/
