Add onTransformEnd method

Author: eduardoboucas

lib/sourcebit.js

@@ -194,6 +194,7 @@ class Sourcebit {
       objects: []
     };
     const contextSnapshot = cloneDeep(this.context);
+    const onTransformEndCallbacks = [];
     const queue = this.pluginBlocks.reduce((queue, pluginBlock, index) => {
       // If the plugin hasn't been bootstrapped, we don't want to run its
       // transform method just yet.
@@ -209,6 +210,18 @@ class Sourcebit {
           return data;
         }
 
+        if (typeof plugin.onTransformEnd === "function") {
+          onTransformEndCallbacks.push({
+            args: {
+              debug: this.getDebugMethodForPlugin(pluginName),
+              getPluginContext: () => contextSnapshot[pluginName] || {},
+              log: this.logFromPlugin.bind(this),
+              options: this.parsePluginOptions(plugin, pluginBlock.options)
+            },
+            callback: plugin.onTransformEnd
+          });
+        }
+
         return plugin.transform({
           data,
           debug: this.getDebugMethodForPlugin(pluginName),
@@ -232,6 +245,10 @@ class Sourcebit {
     try {
       const data = await queue;
 
+      onTransformEndCallbacks.forEach(({ args, callback }) => {
+        callback({ ...args, data });
+      });
+
       finishTransform();
 
       if (Array.isArray(data.files)) {

lib/sourcebit.test.js

@@ -888,6 +888,71 @@ describe("`transform()`", () => {
     expect(error).toBeInstanceOf(Error);
     expect(callbackData).not.toBeDefined();
   });
+
+  test("calls the `onTransformEndFn` callback of each plugin, if defined, when `transform` has finished running", async () => {
+    const onTransformEndFn = jest.fn();
+    const plugins = [
+      {
+        module: {
+          name: "sourcebit-test1",
+          onTransformEnd: onTransformEndFn,
+          transform: async ({ data }) => {
+            return {
+              ...data,
+              elements: [{ name: "Lead" }]
+            };
+          }
+        }
+      },
+      {
+        module: {
+          name: "sourcebit-test2",
+          onTransformEnd: onTransformEndFn,
+          transform: ({ data }) => {
+            return {
+              ...data,
+              elements: data.elements.concat({
+                name: "Rhenium"
+              })
+            };
+          }
+        }
+      },
+      {
+        module: {
+          name: "sourcebit-test3",
+          onTransformEnd: onTransformEndFn,
+          transform: ({ data }) => {
+            return {
+              ...data,
+              elements: data.elements.concat({
+                name: "Osmium"
+              })
+            };
+          }
+        }
+      }
+    ];
+    const callback = jest.fn();
+    const sourcebit = new Sourcebit();
+
+    sourcebit.onTransform = callback;
+    sourcebit.loadPlugins(plugins);
+
+    await sourcebit.bootstrapAll();
+
+    const data = await sourcebit.transform();
+
+    expect(onTransformEndFn).toHaveBeenCalledTimes(3);
+
+    onTransformEndFn.mock.calls.forEach(call => {
+      expect(call[0].debug).toBeInstanceOf(Function);
+      expect(call[0].getPluginContext).toBeInstanceOf(Function);
+      expect(call[0].log).toBeInstanceOf(Function);
+      expect(call[0].options).toEqual({});
+      expect(call[0].data).toEqual(data);
+    });
+  });
 });
 
 describe("writing files", () => {