react-from-text

Create React elements from a string containing markup. Useful for creating nicely-structured translation strings containing HTML-like tags.

Background

You want to build a React app that is translated into multiple languages. To make the translations sound natural, you need to give the translators the flexibility to re-order placeholder items within the translated strings.

For example, suppose you want to include a variable, a link, and some bold text in a sentence to be translated. Ignoring translation requirements, it would be something like this:

function SomeComponent({ prize }) {
  return (
    <div>You will <b>win a {prize}</b> if you <a href="https://example.com/">Click Here</a>!</div>
  );
}

One way to handle this would be to break the text into several chunks and submit them separately to translators. In this case the chunks would be:

"You will"

"win a"

"if you"

"Click Here"

Breaking up the string forces translators to figure out a way to translate the chunks into a well-structured sentence, without changing the order of the chunks.

Example

A better way is to give the translators a full sentence, including markers for the HTML tags and the placeholder variable -- something like:

You will <b>win a %(prizeName)s</b> if you <link>Click Here</link>!

That's where this library comes in:

import fromText from 'react-from-text';
import gettext from '...';

function TranslatedComponent({ prize }) {
  // This example uses `gettext()` for the actual translation substitution,
  // but any function that returns a string works (or even a hard-coded string).
  return (
    <div>
      {
        fromText(
          gettext('You will <b>win a %(prizeName)s</b> if you <link>Click Here</link>!'),
          {
            prizeName: prize,
            b: <b/>,
            link: <a href="https://example.com/"/>,
          }
        )
      }
    </div>
  );
}

Also, as this example shows, the names of the tags don't have to actually match the name of the component that replaces it. You can use tag names that will be helpful to communicate the intent to the translators (such as "link" in this case, where a hypothetical translator might not know what an <a> tag represents.

API Reference

This package exports a function fromText() with the following signature:

function fromText(text, placeholders)

• text (String): The text containing the tags and placeholder markers to replace
• placeholders (Object): A map of placeholder names (from the text) to their replacements. These can take two different forms:
  • A tag (pair or self-closing) in the text is replaced by a React component with specified props
  • An interpolation placeholder in the text is replaced by a value, stringified. This library does not mandate a specific format for the interpolation placeholders in the text. It uses sprintf-js (installed separately as a peer dependency) to replace interpolation placeholders, so "named" sprintf-js placeholder style should be used:

    '%(name)s', '%(name)d', etc.

Credits/Acknowledgements

v1.0.0 (2020-06-11): For v1.0.0 the core was rewritten by Taylor Everding (@taylor1791) to use a cleaner AST-based parsing approach.

v0.1.0 The core of this package was originally a utility (format-message/react) in format-message, with initial work by @vanwagonet and contributions by Paul Robertson (me).

Since that time, format-message has implemented an alternative approach for supporting tags in translation strings, and has deprecated the format-message/react utility. However, the alternative approach is specific to the ICU MessageFormat syntax for translations. In my case I wasn't using format-message with ICU MessageFormat -- I was just using the utility to replace tags in strings with React components -- so it made sense to extract it into its own package. I had also made some React-specific improvements within a private codebase (for example, allowing the same tag name to be used multiple times in a translation string). Those improvements are also included in this package.

My work (and Taylor's work) on this package was funded by my employer, HireVue, Inc. (@hirevue). It's a great place to work -- check us out!