Question

I’ve searched around and I couldn’t find one that really works.

In Mustache, when you throw 2 curly, the string inside will be escaped, and if you throw 3, it will NOT.

// when you pass {foo: '"bar"'} as hash, the following template will be: 
 {{foo}}  // => "bar"
{{{foo}}} // => "bar"

right? So I created the following.

http://jsfiddle.net/beatak/6s5PU/

and this shows interpolate and escape opposite, meaning 2 curly for unescaped 3 for escaped. When I flip between escape and interpolate in _.templateSettings, it just doesn’t work. WHY? Underscore template has precedence of those three (escape, interpolate and evaluate)?

I know I’m ignoring evaluate on jsfiddle now, if that works together that’ll be fantastic, but for now, I want to make 2 and 3 curly works just fine…

Answer 1

The regex for escape is searched, then interpolate, then evaluate. That’s why your escaped form {{ }} is matching before your unescaped form {{{ }}}. You can change the order yourself in the source for _.template.

var matcher = new RegExp([
  (settings.escape || noMatch).source,
  (settings.interpolate || noMatch).source,
  (settings.evaluate || noMatch).source
].join('|') + '|$', 'g');

Changing the order of the lines above will change the priority.

If you don’t want to change the underscore priority, you can use a more complex escaping regular expression. It’s tricky to do without negative look-behind, but I came up with:

/\{\{([^\{\}]+?)(?!\}\}\})\}\}/

which should mean: {{, followed by one or more non-brace characters, that shall not be followed by triple brace (}}}), followed by double brace }}. It works on your fiddle and hopefully will work for you.