chapter 02: making encoderFactory open for extension injecting factories

devcorpio · Mar 30, 2019 · b06e05d · b06e05d
1 parent a14b46f
commit b06e05d
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Showing 2 changed files with 22 additions and 11 deletions.
diff --git a/chapter-02-the-open-closed-principle/refactor/encoderFactory.js b/chapter-02-the-open-closed-principle/refactor/encoderFactory.js
@@ -1,22 +1,21 @@
-const jsonEncoder = require('./jsonEncoder');
-const xmlEncoder = require('./xmlEncoder');
-const yamlEncoder = require('./yamlEncoder');
-
 function encoderFactory() {
+    const factories = {};
+
     function createForFormat(format) {
-        if (format === 'json') {
-            return jsonEncoder();
-        } else if (format === 'xml') {
-            return xmlEncoder();
-        } else if (format === 'yml') {
-            return yamlEncoder();
+        if (typeof factories[format] !== 'function') {
+            throw new Error('Unknown format');
         }
 
-        throw new Error('Unknown format');
+        return factories[format];
+    }
+
+    function addEncoderFactory(format, fn) {
+        factories[format] = fn;
     }
 
     return {
         createForFormat,
+        addEncoderFactory,
     };
 }
 

diff --git a/chapter-02-the-open-closed-principle/refactor/exampleUsingEncoderFactory.js b/chapter-02-the-open-closed-principle/refactor/exampleUsingEncoderFactory.js
@@ -0,0 +1,12 @@
+const encoderFactory = require('./encoderFactory');
+const jsonEncoder = require('./jsonEncoder');
+
+const encoderFactoryIstance = encoderFactory();
+
+encoderFactoryIstance.addEncoderFactory('json', () => {
+    return jsonEncoder();
+});
+
+encoderFactoryIstance.createForFormat('json');
+
+//... xml, yaml...