@@ -0,0 +1,15 @@
+{
+  "changes": [
+    {
+      "comment": "Make web-library-build export the tasks it defines",
+      "packageName": "@microsoft/web-library-build",
+      "type": "minor"
+    },
+    {
+      "comment": "Add documentation to CopyTask",
+      "packageName": "@microsoft/gulp-core-build",
+      "type": "none"
+    }
+  ],
+  "email": "zihankoh@microsoft.com"
+}
@@ -2,12 +2,22 @@ import { GulpTask } from './GulpTask';
 import gulp = require('gulp');
 
 export interface ICopyConfig {
+  /**
+   * Object of dest: [source] for the copy task.
+   */
   copyTo: {
     [destPath: string]: string[];
   };
+
+  /**
+   * Whether to remove or replace relative path for files. True by default.
+   */
   shouldFlatten?: boolean;
 }
 
+/**
+ * This task takes in a map of dest: [sources], and copies items from one place to another.
+ */
 export class CopyTask extends GulpTask<ICopyConfig> {
   public taskConfig: ICopyConfig = {
     copyTo: {},
 
@@ -22,6 +22,7 @@ export * from '@microsoft/gulp-core-build-karma';
 export * from '@microsoft/gulp-core-build-webpack';
 export * from '@microsoft/gulp-core-build-serve';
 
+// pre copy and post copy allows you to specify a map of dest: [sources] to copy from one place to another.
 export const preCopy: CopyTask = new CopyTask();
 preCopy.name = 'pre-copy';
 
@@ -34,30 +35,33 @@ const sourceMatch: string[] = [
 ];
 
 // Define default task groups.
-let buildTasks: IExecutable = task('build', serial(preCopy, sass, parallel(tslint, typescript, text), postCopy));
-let bundleTasks: IExecutable = task('bundle', serial(buildTasks, webpack));
-const postProcessSourceMaps: PostProcessSourceMaps = new PostProcessSourceMaps();
-const validateShrinkwrapTask: ValidateShrinkwrapTask = new ValidateShrinkwrapTask();
-const generateShrinkwrapTask: GenerateShrinkwrapTask = new GenerateShrinkwrapTask();
+export const compileTsTasks: IExecutable = parallel(typescript, text);
+export const buildTasks: IExecutable = task('build', serial(preCopy, sass, parallel(compileTsTasks, text), postCopy));
+export const bundleTasks: IExecutable = task('bundle', serial(buildTasks, webpack));
+export const testTasks: IExecutable = serial(sass, compileTsTasks, karma);
+export const defaultTasks: IExecutable = serial(bundleTasks, karma);
+export const postProcessSourceMapsTask: PostProcessSourceMaps = new PostProcessSourceMaps();
+export const validateShrinkwrapTask: ValidateShrinkwrapTask = new ValidateShrinkwrapTask();
+export const generateShrinkwrapTask: GenerateShrinkwrapTask = new GenerateShrinkwrapTask();
 
 task('validate-shrinkwrap', validateShrinkwrapTask);
 task('generate', generateShrinkwrapTask);
 
-task('test', serial(sass, parallel(typescript, text), karma));
+task('test', serial(sass, testTasks));
 
-task('test-watch', watch(sourceMatch, serial(sass, parallel(typescript, text), karma)));
+task('test-watch', watch(sourceMatch, serial(sass, compileTsTasks, karma)));
 
 // For watch scenarios like serve, make sure to exclude generated files from src (like *.scss.ts.)
 task('serve',
   serial(
     bundleTasks,
     serve,
-    postProcessSourceMaps as any, // tslint:disable-line:no-any
+    postProcessSourceMapsTask,
     watch(
-      sourceMatch, serial(preCopy, sass, parallel(typescript, text),
-      postCopy, webpack, postProcessSourceMaps as any, reload) // tslint:disable-line:no-any
+      sourceMatch, serial(preCopy, sass, compileTsTasks,
+        postCopy, webpack, postProcessSourceMapsTask, reload)
     )
   )
 );
 
-task('default', serial(bundleTasks, karma));
+task('default', defaultTasks);