How can I replace {0} but not {{0}}?

Question

I want to replace all {0} on a string with x. It should not match {{0}}.

How can I do it?

Answer 1

Match either {{0}} or {0}, and replace only those occurances that are {0}.

Something like:

s = s.replace(/(\{\{0\}\}|\{0\})/g, function(m){ return m == '{0}' ? 'x' : m});