Design: i18n

Internationalization

We are using the i18next library for NLS support in both the runtime and editor.

Core Message Catalogs

Component	Namespace	Location
Runtime	runtime	node-red/locales/__lang__/runtime.json
Editor	editor	node-red/locales/__lang__/editor.json
Core nodes	node-red	node-red/nodes/core/locales/__lang__/messages.json

Node Modules Catalogs

A node module provides message catalogs on a per-node-set basis. Given a node-set identified in package.json as:

"node-red": {
    "myNode": "lib/my-node.js"
}

The following message catalogs may exist:

lib/locales/__lang__/my-node.json
lib/locales/__lang__/my-node.html

NB: the locales directory is relative to the node's .js file.

The .json file is the message catalog for both runtime and editor.

The .html file contains the localized node help content. The help content in the top-level .html file may identify what language it provides using a data-lang attribute: (en-US assumed if not set).

<script type="text/x-red" data-help-name="foo" data-lang="en-US">
    <p>A foo node</p>
</script>

The catalog for a node-set is added under the namespace <module>/<set>.

Loading catalogs in the editor

All of this is subject to change - need to figure out how best for the editor to express what language it wants the catalogs in

A node's localized help will automatically get included with the existing methods to retrieve the node's editor configuration.

For message catalogs, a new api end-point is added:

/locales/__namespace__

For example:

/locales/node-red

will load the catalog for all core nodes.

/locales/node-red-contrib-twilio/twilio

will load the catalog for the node-red-contrib-twilio/twilio node set.

Using i18n for messages

Runtime

var i18n = require("./path/to/i18n.js");
// i18n._ is provided as a wrapper to i18next.t

// Retrieve the value of the message `runtime.version`
console.log(i18n._("runtime.version"));

// Retrieve the value of the message `example.insert" with a named insert
//   "example.insert" : "I have a value of __myValue__"
console.log(i18n._("example.insert",{myValue: 123});

Nodes

Nodes can use RED._() to retrieve messages. The function they are provided is pre-scoped to the node's own namespace so they don't have to worry about providing it with each message.

Editor

RED._() is provided for core editor code.

Any html element can set a data-i18n attribute, as documented here. NB: $(element).i18n() must be called after element is added to the DOM in order for these attributes to be parsed.

Nodes

As well as the data-i18n attribute for html elements, all node definition functions (oneditprepare etc) can use this._() to retrieve messages, pre-scoped to the node's namespace.