Extract i18n string into i18n/_defaults (base of translations) (#4514)

* Build script to pull i18n into i18n/_default

* Fix header

* Current strings as extracted

* details_windows without prefix

* clean before build

* Alwasy extract babel strings

* clean & run build before extraction

* Update settings messages

* Put back template string (PR comment)

* PR comment cleanups & logging

* Less complicated string type check (PR comment)

* Remove node cache to extract all keys (Thanks @ngotchac)

* Merge in defaults from i18n/en (Comment by @h3ll0fr13nd)

* Unique index keys only

* Update with latest master strings

* _.defaultsDeep (Thanks to @dehurst)

* Use to-source for string formatting

* Sync with toSource output on latest master

* Updated to use/output sorted objects

js/scripts/build-i18n.js

@@ -0,0 +1,154 @@
+// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+const fs = require('fs');
+const _ = require('lodash');
+const path = require('path');
+const toSource = require('to-source');
+
+const FILE_HEADER = `// Copyright 2015-2017 Parity Technologies (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.\n\n`;
+const SECTION_HEADER = 'export default ';
+const SECTION_FOOTER = ';\n';
+const INDENT = '  ';
+const DESTPATH = path.join(__dirname, '../src/i18n/_default');
+const ENPATH = path.join(__dirname, '../src/i18n/en');
+const SRCPATH = path.join(__dirname, '../.build/i18n/i18n/en.json');
+
+// main entry point
+(function main () {
+  const { sections, sectionNames } = createSectionMap();
+
+  sectionNames.forEach((name) => outputSection(name, sections[name]));
+  outputIndex(sectionNames);
+})();
+
+// sort an object based on its keys
+function sortObject (object) {
+  return Object
+    .keys(object)
+    .sort()
+    .reduce((sorted, key) => {
+      if (typeof object[key] === 'object') {
+        sorted[key] = sortObject(object[key]);
+      } else {
+        sorted[key] = object[key];
+      }
+
+      return sorted;
+    }, {});
+}
+
+// create an object map of the actual inputs
+function createSectionMap () {
+  console.log(`Reading strings from ${SRCPATH}`);
+
+  const i18nstrings = require(SRCPATH);
+  const sections = sortObject(
+    Object
+      .keys(i18nstrings)
+      .reduce((sections, fullKey) => {
+        const defaultMessage = i18nstrings[fullKey].defaultMessage;
+        const keys = fullKey.split('.');
+        let outputs = sections;
+
+        keys.forEach((key, index) => {
+          if (index === keys.length - 1) {
+            outputs[key] = defaultMessage;
+          } else {
+            if (!outputs[key]) {
+              outputs[key] = {};
+            }
+
+            outputs = outputs[key];
+          }
+        });
+
+        return sections;
+      }, {})
+  );
+  const sectionNames = Object.keys(sections);
+
+  console.log(`Found ${sectionNames.length} sections`);
+
+  return {
+    sections,
+    sectionNames
+  };
+}
+
+// load the available deafults (non-exported strings) for a section
+function readDefaults (sectionName) {
+  let defaults = {};
+
+  try {
+    defaults = require(path.join(ENPATH, `${sectionName}.js`)).default;
+  } catch (error) {
+    defaults = {};
+  }
+
+  return defaults;
+}
+
+// create the index.js file
+function outputIndex (sectionNames) {
+  console.log(`Writing index.js to ${DESTPATH}`);
+
+  const defaults = readDefaults('index');
+  const dest = path.join(DESTPATH, 'index.js');
+  const exports = _.uniq(Object.keys(defaults).concat(sectionNames))
+    .sort()
+    .map((name) => `export ${name} from './${name}';`)
+    .join('\n');
+
+  fs.writeFileSync(dest, `${FILE_HEADER}${exports}\n`, 'utf8');
+}
+
+// export a section as a flatenned JS export string
+function createJSSection (section) {
+  const source = toSource(section, {
+    enclose: true,
+    quoteChar: '`',
+    tabChar: INDENT,
+    tabDepth: 0
+  });
+
+  return `${SECTION_HEADER}${source}${SECTION_FOOTER}`;
+}
+
+// create the individual section files
+function outputSection (sectionName, section) {
+  console.log(`Writing ${sectionName}.js to ${DESTPATH}`);
+
+  const defaults = readDefaults(sectionName);
+  const dest = path.join(DESTPATH, `${sectionName}.js`);
+  const sectionText = createJSSection(_.defaultsDeep(section, defaults));
+
+  fs.writeFileSync(dest, `${FILE_HEADER}${sectionText}`, 'utf8');
+}