Small updates

chapter02/src/tagged_templates.js

@@ -0,0 +1,19 @@
+function showAge(strings, name, year) {
+    const currYear = new Date().getFullYear();
+    const yearsAgo = currYear - year;
+    return (
+        strings[0] + name + strings[1] + year + `, ${yearsAgo} years ago`
+    );
+}
+
+const who = "Prince Valiant";
+const when = 1937;
+const output1 = showAge`The ${who} character was created in ${when}.`;
+console.log(output1);
+// The Prince Valiant character was created in 1937, 81 years ago
+
+const model = "Suzuki";
+const yearBought = 2009;
+const output2 = showAge`My ${model} car was bought in ${yearBought}`;
+console.log(output2);
+// My Suzuki car was bought in 2009, 9 years ago