chore(*) add gulp build --with-docs

Now, gulp build task with the flag --with-docs will:
* generate docs in build/docs by running npm run yuidoc
* copy build/docs to build/dist/docs

gulp/paths.js

@@ -56,7 +56,8 @@ const paths = {
       fonts: `${root}/build/dist/fonts/`,
       images: `${root}/build/dist/images/`,
       styles: `${root}/build/dist/styles/`,
-      scripts: `${root}/build/dist/scripts/`
+      scripts: `${root}/build/dist/scripts/`,
+      docs: `${root}/build/dist/docs/`
     },
     docs: `${root}/build/docs/`
   },

gulp/tasks/build.js

@@ -16,7 +16,7 @@ import inject from 'gulp-inject';
 import runSequence from 'run-sequence';
 
 import {BANNER, BANNER_HTML} from '../const';
-import {LOG, COLORS} from '../utils';
+import {LOG, COLORS, WITH_DOCS} from '../utils';
 import paths from '../paths';
 
 //=============================================
@@ -51,7 +51,7 @@ function bytediffFormatter(data) {
 //=============================================
 
 /**
- * The 'clean' task delete 'build' and '.tmp' directories.
+ * The 'clean' task delete 'build/dist' and '.tmp' directories.
  * But keeps build/dist/.git (if you git init this folder to deploy via git)
  */
 gulp.task('clean', (cb) => {
@@ -75,6 +75,35 @@ gulp.task('extras', () => {
     .pipe(gulp.dest(paths.build.dist.basePath));
 });
 
+/**
+ * This task generates doc to `build/docs` and copies it to `build/dist/docs`
+ * It only does it if run with correct flag: `gulp build --with-docs`
+ *
+ * If no flag, does nothing.
+ */
+gulp.task('extras-docs', (cb) => {
+  if(WITH_DOCS){
+    runSequence(
+      ['generate-docs'],
+      ['copy-generated-docs'],
+      (err) => {
+        if (err) {
+          let exitCode = 3;
+          LOG('[ERROR] gulp build task failed (docs generation step)', err);
+          LOG('[FAIL] gulp build task failed (docs generation step) - exiting with code ' + exitCode);
+          return process.exit(exitCode);
+        }
+        else {
+          return cb();
+        }
+      }
+    );
+  }
+  else{
+    return cb();
+  }
+});
+
 /**
  * The 'compile' task compile all js, css and html files.
  *
@@ -132,6 +161,7 @@ gulp.task('build', (cb) => {
   runSequence(
     ['clean'],
     ['compile', 'extras', 'images'],
+    ['extras-docs'],
     (err) => {
       if (err) {
         let exitCode = 2;

gulp/tasks/docs.js

@@ -0,0 +1,30 @@
+'use strict';
+
+import gulp from 'gulp';
+import {exec} from 'child_process';
+
+import paths from '../paths';
+
+/**
+ * This task simply encapsulate the npm task `npm run yuidoc`
+ * so that it could be integrated in the `gulp build --with-docs` workflow
+ */
+gulp.task('generate-docs', (cb) => {
+  return exec('npm run yuidoc', (error, stdout, stderr) => {
+    console.log('stdout: ' + stdout);
+    console.log('stderr: ' + stderr);
+    if (error !== null) {
+      console.log('exec error: ' + error);
+    }
+    cb();
+  });
+});
+
+/**
+ * This task simply copies generated docs from `build/docs` to `build/dist/docs`
+ * `build/docs` must have been generated before
+ */
+gulp.task('copy-generated-docs', () => {
+  return gulp.src(paths.build.docs + '**/*')
+    .pipe(gulp.dest(paths.build.dist.docs));
+});

gulp/utils.js

@@ -31,6 +31,8 @@ LOG(COLORS.yellow('### Running in ' + environment + ' ###'));
 
 export const ENV = environment;
 
+export const WITH_DOCS = util.env['with-docs'];
+
 /**
  * @warn this is still in progress
  *