Add day 1 part ii solution

1/1_2.ts

@@ -0,0 +1,100 @@
+import { LoadInput } from "../common.ts";
+
+/**
+ * Calculate the sum of all calibration values in a document
+ *
+ * @param {string[]} document All lines of a document containing calibration values
+ * @returns {number} The sum of all calibration values found in a document
+ */
+function CalculateCalibrationSum(document: string[]): number {
+	return document.reduce((register, currVal) => register + extractCalibrationValue(currVal), 0);
+}
+
+/**
+ * Extract a calibration value from a line of text
+ *
+ * Extracts the first and last digit from a string of text,
+ * concatenates the two, and returns this as the calibration value.
+ *
+ * If only one digit is present, the one digit is concatenated to
+ * itself.
+ *
+ * @param {string} line The line of text to extract the calibration value out of
+ * @returns {number} The two-digit calibration value hidden in that string 
+ */
+function extractCalibrationValue(line: string): number {
+	const extracter = new RegExp("(?=(one|t(?:wo|hree)|f(?:our|ive)|s(?:ix|even)|eight|nine|[0-9]))", "g");
+	const digitsInString = Array.from(line.matchAll(extracter), (match) => match[1]) || [];
+
+	if (digitsInString.length == 0) {
+		console.error("No digits found on line!");
+		console.error(line);
+	}
+
+	const firstDigit = parseNumberWordToDigit(digitsInString[0]);
+	const secondDigit = parseNumberWordToDigit(digitsInString[digitsInString.length - 1]);
+
+	return Number(firstDigit + secondDigit);
+}
+
+/**
+ * Turn the word representation of a digit into that digit
+ *
+ * @param {string|undefined} numberString A string containing either the word of a number, or the digit
+ * @returns {string} A string of the digit that the input represents
+ */
+function parseNumberWordToDigit(numberString: string|undefined): string {
+	switch (numberString) {
+		case "0":
+		case "1":
+		case "2":
+		case "3":
+		case "4":
+		case "5":
+		case "6":
+		case "7":
+		case "8":
+		case "9":
+			return numberString;
+		case "one":
+			return "1";
+		case "two":
+			return "2";
+		case "three":
+			return "3";
+		case "four":
+			return "4";
+		case "five":
+			return "5";
+		case "six":
+			return "6";
+		case "seven":
+			return "7";
+		case "eight":
+			return "8";
+		case "nine":
+			return "9";
+		default:
+			return "0";
+	}
+}
+
+const tests: string[] = [
+	"two1nine",
+	"eightwothree",
+	"abcone2threexyz",
+	"xtwone3four",
+	"4nineeightseven2",
+	"zoneight234",
+	"7pqrstsixteen",
+	"3pqrstsevenine",
+];
+
+const input = await LoadInput(1);
+
+console.log("Test Cases");
+console.log("Expected: 320")
+console.log(`Actual: ${CalculateCalibrationSum(tests)}\n`);
+
+console.log("Input");
+console.log(`Your *true* calibration sum: ${CalculateCalibrationSum(input)}`);