chapter 05: making fizzBuzz open for extension, step 1

chapter-05-the-dependency-inversion-principle/refactor/buzzRule.js

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+function buzzRule() {
+    function matches(number) {
+        return number % 5 === 0;
+    }
+
+    function getReplacement() {
+        return 'Buzz';
+    }
+
+    return {
+        matches,
+        getReplacement,
+    };
+}
+
+module.exports = buzzRule;

chapter-05-the-dependency-inversion-principle/refactor/fizzBuzz.js

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+function fizzBuzz() {
+    function generateList(limit) {
+        const list = [];
+
+        for (let number = 1; number <= limit; number++) {
+            list.push(generateElement(number));
+        }
+
+        return list;
+    }
+
+    function generateElement(number) {
+        const fizzBuzzRule = fizzBuzzRule();
+
+        if (fizzBuzzRule.matches(number)) {
+            return fizzBuzzRule.getReplacement();
+        }
+
+        if (fizzRule.matches(number)) {
+            return fizzRule.getReplacement();
+        }
+
+        if (buzzRule.matches(number)) {
+            return buzzRule.getReplacement();
+        }
+
+        return number;
+    }
+
+    return {
+        generateList,
+    };
+}
+
+module.exports = fizzBuzz;

chapter-05-the-dependency-inversion-principle/refactor/fizzBuzzRule.js

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+function fizzBuzzRule() {
+    function matches(number) {
+        return number % 3 && number && 5 === 0;
+    }
+
+    function getReplacement() {
+        return 'FizzBuzz';
+    }
+
+    return {
+        matches,
+        getReplacement,
+    };
+}
+
+module.exports = fizzBuzzRule;

chapter-05-the-dependency-inversion-principle/refactor/fizzRule.js

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+function fizzRule() {
+    function matches(number) {
+        return number % 3 === 0;
+    }
+
+    function getReplacement() {
+        return 'Fizz';
+    }
+
+    return {
+        matches,
+        getReplacement,
+    };
+}
+
+module.exports = fizzRule;