README.md

react-messageformat

Installation

$ npm install --save @oursky/react-messageformat
$ yarn add @oursky/react-messageformat

Usage

import * as React from "react";
import * as ReactDOM from "react-dom";
import { LocaleProvider, FormattedMessage } from "@oursky/react-messageformat";

const MESSAGES = {
  "my.message": "Hello World",
};

function Page() {
  return (
    <FormattedMessage id="my.message" />
  );
}

function App() {
  return (
    <LocaleProvider locale="en" messageByID={MESSAGES}>
      <Page />
    </LocaleProvider>
  );
}

ReactDOM.render(<App />, document.getElementById("root"));

Features

• Simple argument {ARG}
• Select {GENDER, select, male{He} female{She} other{They}}
• Ordinal {ORD, selectordinal, one{#st} two{#nd} few{#rd} other{#th}}
• Plural {NUM, plural, one{1 apple} other{# apples}}
• React Element {a, react, href{http://www.example.com} children{a link}}
• Supported values are string, number and React Element.

What is this

This library is a replacement of react-intl

Why

• We use React 16.3 Context API while react-intl uses old context API. By using the new API, we no longer suffer from the caveat of the old API
• We use a more correct parser. The difference can be demonstrated by this script

const React = require("react");
const ReactDOMServer = require("react-dom/server");
const ReactIntl = require("react-intl");
const ReactMessageFormat = require("@oursky/react-messageformat");

const a = ReactDOMServer.renderToString(
  React.createElement(
    ReactIntl.IntlProvider,
    { locale: "en", textComponent: props => props.children },
    React.createElement(ReactIntl.FormattedMessage, {
      id: "a",
      values: { A: "true" },
      defaultMessage: "{A, select, true{} other{}}",
    })
  )
);
console.log("react-intl", a);
// react-intl will emit a warning complaining that it cannot parse the message.
// And it will render the unparsed message as plain string.

const b = ReactDOMServer.renderToString(
  React.createElement(
    ReactMessageFormat.LocaleProvider,
    { locale: "en", messageByID: { a: "{A, select, true{} other{}}" } },
    React.createElement(ReactMessageFormat.FormattedMessage, {
      id: "a",
      values: { A: "true" },
    })
  )
);
console.log("react-messageformat", b);
// b is an empty string.

• We write the evaluation function ourselves. The evaluation function evaluates the AST to an array, which is a first class React element. So we support nesting any react element. react-intl uses a hack to support nesting react element.