Add localization support #45

lib/engine.js

@@ -6,6 +6,8 @@ const pify = require('pify');
 const load = require('load-whatever');
 const Handlebars = require('handlebars');
 const extractStack = require('extract-stack');
+const folderToObject = require('folder-to-object');
+const assign = require('lodash.assign');
 const glob = pify(require('glob'));
 
 const readFile = pify(fs.readFile);
@@ -48,6 +50,10 @@ class PaniniEngine {
     return glob(globPath).then(paths => Promise.all(paths.map(p => cb(p))));
   }
 
+  get i18n() {
+    return this.locales.length > 0;
+  }
+
   /**
    * Set up common settings for all rendering engines. Because `PaniniEngine` is considered an
    * abstract class, this constructor will never be called directly.
@@ -58,8 +64,13 @@ class PaniniEngine {
       throw new TypeError('Do not call the PaniniEngine class directly. Create a sub-class instead.');
     }
 
-    this.options = options || {};
+    this.options = assign({
+      data: 'data',
+      locales: 'locales'
+    }, options || {});
     this.data = {};
+    this.locales = [];
+    this.localeData = {};
 
     if (this.supports('layouts')) {
       this.layouts = {};
@@ -74,12 +85,18 @@ class PaniniEngine {
     const extensions = '**/*.{js,json,yml,yaml,cson}';
     this.data = {};
 
-    return this.constructor.mapPaths(this.options.input, this.options.data, extensions, filePath => {
-      return load(filePath).then(contents => {
-        const name = path.basename(filePath, path.extname(filePath));
-        this.data[name] = contents;
-      });
-    });
+    return Promise.all([
+      this.constructor.mapPaths(this.options.input, this.options.data, extensions, filePath => {
+        return load(filePath).then(contents => {
+          const name = path.basename(filePath, path.extname(filePath));
+          this.data[name] = contents;
+        });
+      }),
+      folderToObject(path.join(this.options.input, this.options.locales)).then(res => {
+        this.locales = Object.keys(res);
+        this.localeData = res;
+      })
+    ]);
   }
 
   /**

lib/panini.js

@@ -10,6 +10,7 @@ const templateHelpers = require('template-helpers');
 const handlebarsHelpers = require('handlebars-helpers');
 const pathPrefix = require('path-prefix');
 const tryRequire = require('try-require');
+const translateHelper = require('./translate');
 const render = require('./render');
 const repeat = require('./repeat');
 
@@ -29,6 +30,7 @@ module.exports = class Panini extends EventEmitter {
       helpers: 'helpers',
       data: 'data',
       filters: 'filters',
+      locales: 'locales',
       pageLayouts: {},
       engine: 'handlebars',
       builtins: true,
@@ -174,26 +176,34 @@ module.exports = class Panini extends EventEmitter {
         // Layout used by this page
         layout,
         // Path prefix to root directory
-        root: pathPrefix(file.path, path.join(this.options.input, this.options.pages))
+        root: pathPrefix(file.path, path.join(this.options.input, this.options.pages)),
+        // Locale
+        locale: file.data && file.data.paniniLocale
       },
       // Helpers
-      this.getHelpers()
+      this.getHelpers(file)
     );
   }
 
-  getHelpers() {
+  getHelpers(file) {
     if (!this.options.builtins) {
       return {};
     }
 
+    const coreHelpers = {};
+
+    if (this.engine.i18n && file.data && file.data.paniniLocale) {
+      coreHelpers.translate = translateHelper(this.engine.localeData, file.data.paniniLocale);
+    }
+
     if (this.options.engine === 'handlebars') {
       return {
-        helpers: assign({repeat}, handlebarsHelpers())
+        helpers: assign({repeat}, coreHelpers, handlebarsHelpers())
       };
     }
 
     return {
-      helpers: templateHelpers()
+      helpers: assign({}, coreHelpers, templateHelpers())
     };
   }
 

lib/render.js

@@ -1,9 +1,11 @@
 'use strict';
 
+const path = require('path');
 const fm = require('front-matter');
 const through = require('through2');
 const assign = require('lodash.assign');
 const replaceExt = require('replace-ext');
+const pathInsert = require('path-insert');
 
 /**
  * Create a transform stream to render a set of pages to HTML.
@@ -17,10 +19,18 @@ module.exports = function () {
   const pages = [];
 
   return through.obj((file, enc, cb) => {
+    // Wait until the `setup()` function of the rendering engine is done
     inst.onReady().then(() => {
       inst.emit('parsing');
-      const page = parse.call(inst, file);
-      pages.push(page);
+
+      if (this.engine.i18n) {
+        // For sites using i18n, the file is duplicated, once for each locale
+        const pageList = makeLocaleFiles.call(inst, file).map(f => parse.call(inst, f));
+        pages.push.apply(pages, pageList);
+      } else {
+        const page = parse.call(inst, file);
+        pages.push(page);
+      }
       cb();
     });
   }, function (cb) {
@@ -29,6 +39,30 @@ module.exports = function () {
   });
 };
 
+/**
+ * Duplicate the file for a single page so there's one for each locale. The base path of the file is modified to insert the locale as a folder. So, `index.html` becomes `en/index.html`, `es/index.html`, `jp/index.html`, and so on.
+ * @param {Object} file - Vinyl file.
+ * @returns {Object[]} Locale-specific versions of file.
+ */
+function makeLocaleFiles(file) {
+  const base = path.join(process.cwd(), this.options.input, this.options.pages);
+
+  return this.engine.locales.map(locale => {
+    const newFile = file.clone();
+
+    // Insert the language code at the base of the path
+    newFile.path = pathInsert.start(file.path, base, locale);
+
+    // The `paniniLocale` key is used to correctly render translation strings
+    if (newFile.data) {
+      newFile.data.paniniLocale = locale;
+    } else {
+      newFile.data = {paniniLocale: locale};
+    }
+    return newFile;
+  });
+}
+
 /**
  * Get the body and data of a page and store it for later rendering to HTML. This is a stream transform function.
  * @param {object} file - Vinyl file being parsed.

lib/translate.js

@@ -0,0 +1,13 @@
+const dotProp = require('dot-prop');
+
+module.exports = (translations, locale) => {
+  return key => {
+    const string = dotProp.get(translations[locale], key);
+
+    if (typeof string === 'undefined') {
+      return key;
+    }
+
+    return string;
+  };
+};

package.json

@@ -15,8 +15,10 @@
     "chalk": "^1.1.3",
     "chokidar": "^1.6.1",
     "deepmerge": "^1.3.2",
+    "dot-prop": "^4.1.1",
     "extract-stack": "^1.0.0",
     "flexiconfig": "^2.0.0",
+    "folder-to-object": "^1.0.0",
     "front-matter": "^2.0.5",
     "glob": "^7.0.0",
     "glob-watcher": "^3.1.0",
@@ -29,6 +31,7 @@
     "marked": "^0.3.6",
     "meow": "^3.7.0",
     "ora": "^1.1.0",
+    "path-insert": "^1.0.0",
     "path-prefix": "^1.0.0",
     "pify": "^2.3.0",
     "replace-ext": "^1.0.0",

test/engine.js

@@ -22,7 +22,7 @@ describe('PaniniEngine', () => {
     it('stores options', () => {
       const opts = {input: 'src'};
       const e = new Engine(opts);
-      expect(e.options).to.eql(opts);
+      expect(e.options).to.have.property('input', opts.input);
     });
 
     it('creates an object for layouts if the engine supports it', () => {
@@ -37,9 +37,19 @@ describe('PaniniEngine', () => {
     class Engine extends PaniniEngine {}
 
     it('loads data', () => {
-      const e = new Engine({input: 'test/fixtures/data', data: 'data'});
+      const e = new Engine({input: 'test/fixtures/data'});
       return e.setup().then(() => expect(e.data).to.have.keys(['breakfast']));
     });
+
+    it('stores list of locales', () => {
+      const e = new Engine({input: 'test/fixtures/locales'});
+      return e.setup().then(() => expect(e.locales).to.have.eql(['en', 'jp']));
+    });
+
+    it('loads locale data', () => {
+      const e = new Engine({input: 'test/fixtures/locales'});
+      return e.setup().then(() => expect(e.localeData).to.have.keys(['en', 'jp']));
+    });
   });
 
   describe('supports()', () => {

test/fixtures/locales/locales/en.json

@@ -0,0 +1,3 @@
+{
+  "panini": "Panini"
+}

test/fixtures/locales/locales/jp.json

@@ -0,0 +1,3 @@
+{
+  "panini": "パニニ"
+}