Added the lesson to take apart files for their translation.

exercises/05_take_me_apart/exercise.js

@@ -0,0 +1,15 @@
+var exercise = require('../../lib/exercise')
+var path = require('path')
+
+module.exports = exercise(__dirname, {
+  createSampleSets: function createSampleSets() {
+    var samples = []
+    samples.push({
+      data: path.join(__dirname, 'templates')
+    })
+    return samples
+  },
+  handleResult: function (input, output, __) {
+    return output.join('\n')
+  }
+})

exercises/05_take_me_apart/problem.en.md

@@ -0,0 +1,44 @@
+Write a script that gets all the translation strings within a folder.
+You will receive a folder like:
+
+```javascript
+module.exports = function (folderName) {
+  var translationKeys = []
+  // Fill translationKeys with all the translations in this folder
+  return translationKeys
+}
+```
+
+The folder will contain multiple `.js` files in the folder and subfolders.
+You will need to look out for translation strings like `__` or `.__`.
+
+---
+
+## Hints
+
+### Processing the code
+
+You can write your own code to process the code or you can use one of the many
+modules in NPM. The package `xgettext-js` should come in handy.
+The version `1.1.0` is bundled with this workshopper:
+
+```javascript
+require('{rootdir}/node_modules/xgettext-js')
+```
+
+The readme is available here:
+
+    {rootdir}/node_modules/xgettext-js/README.md
+
+### Finding in Files
+
+Instead of using Node.js's `fs.readdir` it is easier to use the npm module `glob`.
+Version `^7.1.1` is bundled with this workshopper:
+
+```javascript
+require('{rootdir}/node_modules/glob')
+```
+
+The readme is available here:
+
+    {rootdir}/node_modules/glob/README.md

exercises/05_take_me_apart/review.en.md

@@ -0,0 +1,51 @@
+## Review
+
+You can use the code you wrote already in the production pipeline. You might
+want to improve the performance by writing the code in an async fashion.
+
+### Frontend & Backend
+
+This technique is very important _(and standard)_ if your repository contains both
+Frontend and Backend code. As developer, you usually want to be able to maintain
+the same translations for both sides.
+
+For performance reasons you might not want to send all the translations to the
+Frontend.
+
+Also, for security reasons you might want to separate security sensitive
+translations (welcome mails for private guests, pricing documents, etc.) to
+be only loaded to the Frontend once the permission for this data is given.
+
+### Dynamic Keys
+
+Using scripts to look for the usage of translation is usually a good idea.
+However, if you have dynamic use of translation like the following can undercut
+your efforts:
+
+```javascript
+__('exercise.' + exercise.name)
+```
+
+In this case your parser has one of two options:
+
+1. **Ignore this statement** (or give a warning). This is problematic because it would be really good to know which keys are needed.
+2. **Treat this use as an error.** This is problematic because you might actually need to use translations like this sometimes.
+
+With a bit of work at the parser it would be possible to create patterns like:
+
+```
+exercise.*
+*.exercise
+*.exercise.*.error
+```
+
+... and check extract the available translation fields for all possible exercise
+combinations.
+
+### XGetText
+
+`gettext` is the is the standard tool for translation in C. The original
+`xgettext` is a tool that extracts the `gettext` usage in C and C++ files.
+In NPM there is a list of other `xgettext` variants for other file formats:
+
+    https://www.npmjs.com/search?q=xgettext

exercises/05_take_me_apart/solution.js

@@ -0,0 +1,19 @@
+var glob = require('glob')
+var fs = require('fs')
+var path = require('path')
+var xgettextJS = new (require('xgettext-js'))({
+  keywords: {'__': 1}
+})
+
+module.exports = function (folder) {
+  var files = glob.sync('**/*.js', {cwd: folder})
+  return Object.keys(files.reduce(function (allKeys, file) {
+    file = path.join(folder, file)
+    return xgettextJS
+      .getMatches(fs.readFileSync(file, 'utf8'))
+      .reduce(function (allKeys, key) {
+        allKeys[key.string] = true
+        return allKeys
+      }, allKeys)
+  }, {}))
+}

exercises/05_take_me_apart/templates/a.js

@@ -0,0 +1,12 @@
+__('$key: regular')
+
+// Twice to make sure that duplicates are removed
+__('$key: regular')
+
+function hi() {
+  __('$key: unexported function')
+}
+
+module.exports = () => {
+  __('$key: exported function')
+}

exercises/05_take_me_apart/templates/b.js

@@ -0,0 +1,19 @@
+__('$key: Regular key with a property', 'a')
+
+someObj.__('$key: usage as an object property')
+
+someObj.
+
+__('$key: usage as an object property over several lines')
+
+function hi() {
+  __('$key: inside a unexported, unused method scope', 'b')
+  var a = '$key: '
+  __(a + 'advanced usage where the key is split')
+}
+
+module.exports = () => {
+  __('$key: regular within an exported method')
+  __;
+  ('$key: looks like a key is just a string')
+}

exercises/05_take_me_apart/templates/c.md

@@ -0,0 +1,5 @@
+# This is a markdown file to mark that you shouldn't use markdown files
+
+```javascript
+__('$key: Do not look in markdown files')
+```

i18n-it-all.js

@@ -16,7 +16,8 @@ i18nItAll.addAll([
   '01_dynamic_output',
   '02_i_my_me_mine',
   '03_rocket_science',
-  '04_negotiate_with_everyone'
+  '04_negotiate_with_everyone',
+  '05_take_me_apart'
 ])
 
 module.exports = i18nItAll

i18n/en.json

@@ -12,7 +12,8 @@
     "01_dynamic_output": "Dynamic Output",
     "02_i_my_me_mine": "I my me mine",
     "03_rocket_science": "Rocket Science",
-    "04_negotiate_with_everyone": "Negotiate with everyone"
+    "04_negotiate_with_everyone": "Negotiate with everyone",
+    "05_take_me_apart": "Take me apart"
   },
   "negotiate_with_everyone": {
     "headers": "Process the request headers.",

package.json

@@ -31,13 +31,15 @@
     "diff": "^3.0.1",
     "exec-module": "^1.0.0",
     "gettext": "0.0.1",
+    "glob": "^7.1.1",
     "js-quantities": "1.6.3",
     "leftpad": "0.0.0",
     "locale": "0.1.0",
     "lodash.sample": "^4.2.1",
     "lodash.samplesize": "^4.2.0",
     "lodash.zipwith": "^4.2.0",
-    "workshopper-adventure": "^5.1.1"
+    "workshopper-adventure": "^5.1.1",
+    "xgettext-js": "^1.1.0"
   },
   "repository": {
     "type": "git",