Translating multi-line strings in javascript with django

django, gettext, javascript

Solution

The reason it doesn't work automatically is that `makemessages` doesn't use a real javascript parser. It does a minor transformation and applies a C parser. But in order to concatenate strings in javascript you need a `+` character, but in C you must not have any tokens between the strings to be concatenated.

I finally found a workaround, that works:

var $text = gettext('Lorem ipsum dolor sit amet, consectetur adipisicing ' //\
                    +
                    'elit, sed do eiusmod tempor incididunt ut labore et ' //\
                    +
                    'dolore magna aliqua. Ut enim ad minim veniam, quis ');

The javascript parser in the browser will see `//\` as a comment, and find `+` characters between each string as needed. When using `makemessages` the `\` character is parsed as line continuation, and both `//\` as well as the `+` on the following line is considered to be a single comment. So the parser sees string constants separated by just a comment, and implicit string concatenation is performed.

I found this workaround by accident as I came across this piece of code from a fellow developer:

// IE8 only allows string, identifier and number keys between {}s
var parse_bool = {"null": null, "true": true, "false": false}
parse_bool[undefined] = null
parse_bool[null] = null            // using null/true/false *this* way works
parse_bool[true] = true            //  _______
parse_bool[false] = false          // ( WAT?! )
                                   //  ¯¯¯¯¯¯¯ o  ^__^
var render_bool = {}               //           o (oo)\_______
render_bool[null] = '--'           //             (__)\       )\/\
render_bool[true] = gettext('yes') //                 ||----w |
render_bool[false] = gettext('no') //                 ||     ||

When `makemessages` was processing this piece of javascript code, it missed the `yes` string.

Problem

I am working on a django application, which need to support multiple languages. This application involves some amount of javascript code. In this javascript code, there are some multi-line strings, which need to be translated. We have tried this structure: ``` var $text = gettext('Lorem ipsum dolor sit amet, consectetur adipisicing ' + 'elit, sed do eiusmod tempor incididunt ut labore et ' + 'dolore magna aliqua. Ut enim ad minim veniam, quis '); ``` This does not work. `makemessages` stops at the first `+` sign, so in the `.po` file it shows up as: ``` msgid "Lorem ipsum dolor sit amet, consectetur adipisicing " ``` A bit of searching on the net lead to a style guide, which recommends the format we are already using for multi-line strings. But that style is not supported by `makemessages`. I tried removing the `+` characters at the end of the lines. Without the `+` characters, `makemessages` can find the full string, but it no longer works in the browser. Does there exist a style for multi-line strings, which is both supported by `makemessages` and can be expected to work in all major browsers? So far I have found that what `makemessages` is actually doing is to replace all single-quoted strings with double-quoted strings and runs the result through `xgettext` claiming it to be C code.

Original source