chapter 01: creating simpleParser example

Author: devcorpio

chapter_01-the_basics_of_unit_testing/SimpleParser/simpleParser.js

@@ -0,0 +1,26 @@
+const InvalidOperationError = require('./InvalidOperationError');
+
+function simpleParser() {
+    /**
+     * @param {string} numbers
+     * @return {number}
+     */
+    function parseAndSum(numbers) {
+        if (numbers.length === 0) {
+            return 0;
+        }
+        if (!numbers.includes(',')) {
+            return Number(numbers);
+        } else {
+            throw new InvalidOperationError(
+                'I can only handle 0 or 1 numbers for now!'
+            );
+        }
+    }
+
+    return {
+        parseAndSum,
+    };
+}
+
+module.exports = simpleParser;