/**
* Returns the N-th digit of a BigInt counting from the left.
*
* Examples:
* getDigitFromLeftBigInt(12345n, 1) === 1
* getDigitFromLeftBigInt(12345n, 3) === 3
* getDigitFromLeftBigInt(12345n, 5) === 5
*
* @param {bigint} number - The input BigInt.
* @param {number} position - The digit position (1-based, from the left).
* @returns {number} The digit at the specified position.
* @throws {TypeError} If number is not a BigInt.
* @throws {RangeError} If position is invalid.
*/
function getDigitFromLeftBigInt(number, position) {
if (typeof number !== "bigint") {
throw new TypeError("Number must be a BigInt.");
}
if (!Number.isInteger(position) || position < 1) {
throw new RangeError("Position must be a positive integer.");
}
// Convert the absolute value to a string.
const digits = (number < 0n ? -number : number).toString();
if (position > digits.length) {
throw new RangeError("Position is out of range.");
}
return Number(digits[position - 1]);
}
// Example usage
console.log(getDigitFromLeftBigInt(18092n, 3));
console.log(getDigitFromLeftBigInt(180927345162343n, 4));
console.log(getDigitFromLeftBigInt(180927365162341n, 8));
console.log(getDigitFromLeftBigInt(123180927345162341n, 12));
/*
run:
0
9
6
5
*/
