inline-l10n is a ridiculously simple localization preprocessor and micro-library for any kind of plain-text file. It is designed to be simple to use and easy to debug, and works independently of any specific localization format such as gettext or .properties files.

To use it, simply surround any localizable strings in your text file with L10N[[[ on the left side and ]]] on the right side. This usage is similar to gettext's _() function: when localizing, the source string will be used as a key to find a translation. For example, suppose your text file contains the following line:


When localizing, the string hello will be used as a key for which a translation will be sought. If one is found—let's say it's bonjour—then the localized output will be:


However, if no translation is found, the output will be:


Alternatively, if you'd prefer to specify your own key names for locating translations, you can surround the left side of a string with L10N:keyname[[[, where keyname is the name of the key you'd like to use. For example:

<p>L10N:warning-msg[[[that might be a bad idea!]]]</p>

Then a translation will be sought for warning-msg, rather than that might be a bad idea!.

Multi-line Strings

Note also that localizable strings can span multiple lines, so this works:

   Whoa dude, that might be a really bad idea. Are you
   quite certain you'd like to proceed?]]]</p>

Character Escaping

To keep things simple and debuggable, this library doesn't ever escape the contents of localizations. If you're writing HTML in a localizable string and need to write L10N[[[ or ]]], you can use L10N&#91;&#91;&#91; and &#93;&#93;&#93; instead, respectively.


Because this library doesn't escape the contents of localizations, it's assumed that all localized strings are trusted.

define(function() {
  var L10N_RE = /L10N(?:\:([a-z\-]+))?\[\[\[([\s\S]+?)\]\]\]/g;


InlineL10n() is the primary localization function that takes a string to be localized and an object mapping key names to translations. For example:

InlineL10n('<p>L10N[[[hello]]]</p>', {'hello': 'bonjour'});

will return the string <p>bonjour</p>.

  var InlineL10n = function InlineL10n(str, l10n) {
    return str.replace(L10N_RE, function(match, key, value) {
      if (!key)
        key = value;
      if (key in l10n)
        return l10n[key];
      return value;
    return str;

Scanning For Localizable Strings

Most localization code needs to "scrape" its files to find localizable content. InlineL10n.parse() can be used to return an object mapping key names to their default values. For example:

InlineL10n('<p>L10N[[[hello]]] L10N:lol[[[meh]]]</p>');

will return {hello: "hello", lol: "meh"}.

  InlineL10n.parse = function InlineL10n_parse(str) {
    var defaultValues = {};
    str.replace(L10N_RE, function(match, key, value) {
      if (!key)
        key = value;
      defaultValues[key] = value;
    return defaultValues;
  return InlineL10n;