[英]Tutorial: solution for node.js / Polymer i18n based on L20n library
首先,我創建了一個項目結構,該結構將文件分開存放,並按用途分組:
.
+-- app.js
+-- piblic
| +-- locales
| +-- app.ru.l20n
| +-- app.en.l20n
|
+-- node_models
| +-- l20n
|
+-- bower_components
| +-- Polymer libraries
|
+-- app_modules
| +-- app-l20n-node
| +-- index.js
|
+-- app_components
+-- app-l20n
+-- app-l20n.html
+-- app-custom-component
+-- app-custom-component.html
這個想法很簡單: app-l20n-node
用作本地化所有服務器端作業的模塊, app-l20n
是用戶界面app-l20n
的Polymer組件。
運行npm install l20n --save
當前版本是3.5.1,並且有一個小錯誤。 l20n的主文件是./dist/compat/node/l20n.js
,它具有兩個必需的變量,這些變量在代碼中的任何位置均未使用,但可能會在啟動時破壞應用程序,因為它們僅在庫的Devdependency中提及。 為了避免這種情況,我只是在庫代碼中對它們進行了注釋:
//var string_prototype_startswith = require('string.prototype.startswith');
//var string_prototype_endswith = require('string.prototype.endswith');
我在/public/locales/
文件夾中創建了翻譯文件,命名為app.ru.l20n
和app.en.l20n
。 根據L20n規則,文件內容如下所示:
<foo "Foo translation">
<bar "Bar translation">
<register[$variant] {
infinitive: "Register now!"
}>
現在是時候為L20n創建節點模塊了。 在我的情況下, app_modules\\app-l20n-node\\index.js
的代碼如下:
'use strict';
const L20n = require('l20n');
var path = require('path');
module.exports = function(keys, lang){
const env = new L20n.Env(L20n.fetchResource);
// Don't forget nice debug feature of L20n library
env.addEventListener('*', e => console.log(e));
// I suppose that I'll always provide locale code for translation,
// but if it would not happen, module should use preset
var langs = [];
if(!lang) {
// you should define locales here
langs = [{code: 'ru'}, {code: 'en'}]
} else {
langs = [{code: lang}]
}
// set context, using path to locale files
const ctx = env.createContext(langs,
[path.join(__dirname, '../../public/locales/app.{locale}.l20n')]);
const fv = ctx.formatValues;
return fv.apply(ctx, keys);
};
現在,我們可以在node.js代碼中使用此模塊,並按鍵和語言環境的要求獲取翻譯。 我使用硬express-sessions
代替硬編碼的語言環境,並將用戶定義的語言環境存儲為會話屬性req.session.locale
。 但這一切都取決於項目。
var l20n = require('../../app_modules/app-l20n-node');
l20n(['foo','bar'], 'en')
.then((t)=>{
console.log(t); // ["Foo translation", "Bar translation"]
});
現在,我們應該為L20n創建一個Polymer組件。
首先,添加庫並將翻譯文件的鏈接添加到您的html <head>
:
<script src="/node_modules/l20n/dist/compat/web/l20n.js"></script>
<link rel="localization" href="/locales/app.{locale}.l20n">
現在該創建具有新行為的Polymer組件app-l20n.html
了。
<script>
/**
* Create namespace for custom behavior or use existing one.
*/
window.MB = window.MB || {};
MB.i18n = {
/**
* Use l20n.js to translate certain strings
* @param component A Polymer component, usually "this.translate(this, props);"
* @param props An array of keys to translate: strings or arrays.
*/
translate: function(component, props) {
var view = document.l10n;
var promise = view.formatValues.apply(view, props);
promise.then(function(args){
for (var i in args){
var prop = props[i];
// strings with parameters represented by arrays:
// ["string", {param: value}]
if (Array.isArray(prop)) {
// get property name - usually the same, as translation key
// so the object would have properties obj.Foo and obj.Bar
var propName = prop[0];
// if it is needed to create multiple translations of the same
// string in one component, but with different parameters,
// the best way is to use suffix:
// ["string", {param: value}, "_suffix"]
if (prop.length == 3) propName = propName + prop[2];
component.set(propName, args[i]);
}
// common strings
else component.set(prop, args[i]);
}
});
}
};
</script>
不可以,因為新行為已經准備就緒,我們可以在自定義的Polymer組件中實現它。 您可以通過Polymer Behavior或使用L20n自定義標簽屬性功能以編程方式獲得翻譯。
<link rel="import" href="/bower_components/polymer/polymer.html">
<link rel="import" href="/bower_components/gold-email-input/gold-email-input.html">
<link rel="import" href="/bower_components/paper-button/paper-button.html">
<link rel="import" href="/app_components/app-l20n/app-l20n.html">
<dom-module id="app-custom-component">
<template>
<gold-email-input
auto-validate
required
name="email"
value="{{Foo}}"
label="{{Bar}}">
</gold-email-input>
<paper-button onclick="regFormSubmit(event)">
<iron-icon icon="perm-identity"></iron-icon>
<span data-l10n-id="Register" data-l10n-args='{"variant": "infinitive"}'></span>
</paper-button>
</template>
<script>
function regFormSubmit(event){}
Polymer({
is: 'app-custom-component',
behaviors: [
MB.i18n
],
ready: function(){
this.$.passwordValidator.validate = this._validatePasswords.bind(this);
// add your component properties to array. They can be simple like in this example, or
// more complex, with parameters: ["Some_key", {param: "xxx"}].
// you can even translate the same string in different properties, using custom suffix:
// ["Some_key", {param: "yyy"}, "_suffix"] and place it in template with shortcut: {{Some_key_suffix}}
var translateProps = ["Foo", "Bar"];
// now translate, using behavior
this.translate(this, translateProps);
}
});
</script>
</dom-module>
希望本小教程對您有所幫助。
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