Regex

        var str = "abla  mla  atra  lala baaaaaaaaba";
        var re = /[a-z]{2,4}/g;
        var matches = str.match(re);

        // var re = new RegExp("\\w+") (same as) /\w+/

        // ^ begin of string or NOT [^a]
        // $ end of string

        // g -> (after ending slash) gives all matches (without g only first one)
        // i -> (after ending slash) ignore case

        // () -> grouping
        // {n} exactly n occurrences of preceding item
        // {n,} n occurrences or more occurrences of preceding item
        // {n,m} n <-> m interval of occurrences of preceding item

        // \w -> [A-Za-z0-9_]
        // \s -> single whitespace
        // \b -> boundary between space and letter (wrap word)
        //var re = /\b\w*[a{3}]+\b/g;


        // * -> 0 or more matches of preceding item
        // + -> 1 or more matches of preceding item
        // ? -> 0 or 1 matches of preceding item
        // . -> 1 any char

        // x|y -> or