Initial working version

lib/utility.js

@@ -0,0 +1,23 @@
+/**
+ * Utility methods for costructing Scratch project summaries.
+ */
+class Utility {
+    /**
+     * Tallys term frequency from an array of strings.
+     * @param  {array} input Array of strings
+     * @return {object}      Frequency information
+     */
+    static frequency (input) {
+        const result = Object.create(null);
+
+        for (let i in input) {
+            var term = input[i];
+            if (typeof result[term] === 'undefined') result[term] = 0;
+            result[term]++;
+        }
+
+        return result;
+    };
+}
+
+module.exports = Utility;