replace.java

public static String replace(String pattern, String input, Function<String, String> translate){
    Pattern p = Pattern.compile(pattern);
    Matcher m = p.matcher(input);

    StringBuffer result = new StringBuffer();
    while(m.find()){
        String r = translate.apply(m.group());
        m.appendReplacement(result, Matcher.quoteReplacement(r));
    }
    m.appendTail(result);
    return result.toString();
}

public static String replaceSymbols(String input, Function<String, String> translate){
    Map<String, String> cache = new HashMap<String, String>();
    return replace("\\$[a-zA-Z]\\w*", input, s -> {
        if(!cache.containsKey(s)){ cache.put(s, translate.apply(s)); }
        return cache.get(s);
    });
}

replace.js

function ReplaceSymbols(input, translate) {
    var cache = {};
    return input.replace(/$[a-zA-Z]\w*/g, function(symbol){
        if(cache[symbol] == null) { cache[symbol] = translate(symbol); }
        return cache[symbol];
    });
}