如何获取字符串中可能重叠的匹配项

我正在寻找一种方法，无论是在 Ruby 还是 Javascript 中，它都能为我提供字符串中与正则表达式匹配的所有匹配项（可能重叠）。

假设我有str = "abcadc"，我想找到出现的a后跟任意数量的字符，后跟c。我正在寻找的结果是["abc", "adc", "abcadc"]。关于如何实现这一目标有什么想法吗？

str.scan(/a.*c/)会给我["abcadc"], str.scan(/(?=(a.*c))/).flatten会给我["abcadc", "adc"].

def matching_substrings(string, regex)
  string.size.times.each_with_object([]) do |start_index, maching_substrings|
    start_index.upto(string.size.pred) do |end_index|
      substring = string[start_index..end_index]
      maching_substrings.push(substring) if substring =~ /^#{regex}$/
    end
  end
end

matching_substrings('abcadc', /a.*c/) # => ["abc", "abcadc", "adc"]
matching_substrings('foobarfoo', /(\w+).*\1/) 
  # => ["foobarf",
  #     "foobarfo",
  #     "foobarfoo",
  #     "oo",
  #     "oobarfo",
  #     "oobarfoo",
  #     "obarfo",
  #     "obarfoo",
  #     "oo"]
matching_substrings('why is this downvoted?', /why.*/)
  # => ["why",
  #     "why ",
  #     "why i",
  #     "why is",
  #     "why is ",
  #     "why is t",
  #     "why is th",
  #     "why is thi",
  #     "why is this",
  #     "why is this ",
  #     "why is this d",
  #     "why is this do",
  #     "why is this dow",
  #     "why is this down",
  #     "why is this downv",
  #     "why is this downvo",
  #     "why is this downvot",
  #     "why is this downvote",
  #     "why is this downvoted",
  #     "why is this downvoted?"]