Update 2018: This question was asked long before PostCSS existed, and I would have probably used that.
I\'d like to par
Update: I previously mentioned JSCSSP, which is buggy seems to be abandoned. Obviously enough, the css module on NPM is the best:
css = require 'css'
input = '''
body {
font-family: sans-serif;
}
#thing.foo p.bar {
font-weight: bold;
}
'''
obj = css.parse input
sheet = obj.stylesheet
for rule in sheet.rules
rule.selectors = ('#XXX ' + s for s in rule.selectors)
console.log css.stringify(obj)
Output:
#XXX body {
font-family: sans-serif;
}
#XXX #thing.foo p.bar {
font-weight: bold;
}