add support for markdown text

lib/reading_time.ex

@@ -5,11 +5,50 @@ defmodule ReadingTime do
 
   @split_pattern [" ", "\n", "\r", "\t"]
   @words_per_minute 200
+  @markdown_words [
+    # ignore headers
+    ~r/#+/,
+    ~r/(==)+/,
+    ~r/(--)+/,
+    # ingore boxed text
+    ~r/>+/,
+    # ignore unordered lists
+    ~r/-/,
+    ~r/(\*)/,
+    ~r/(\+)/,
+    # ignore horizontal rules
+    ~r/---+/,
+    ~r/\*\*(\*)+/,
+    ~r/___+/,
+  ]
+
+  defp markdown_word?(word) do
+    Enum.any?(
+      @markdown_words,
+      fn md_word ->
+        Regex.match?(md_word, word)
+      end
+    )
+  end
+
+  defp ignore_format_words(words, :text) do
+    words
+  end
+
+  defp ignore_format_words(words, :markdown) do
+    words
+    |> Enum.filter(
+      fn word ->
+        !markdown_word?(word)
+      end
+    )
+  end
 
   @spec time(
           String.t(),
           words_per_minute: non_neg_integer(),
-          split_pattern: nonempty_list(String.t())
+          split_pattern: nonempty_list(String.t()),
+          format: atom()
         ) :: number
   @doc """
   Returns the time in minutes for a given string.
@@ -26,10 +65,11 @@ defmodule ReadingTime do
   def time(string, opts \\ []) do
     words_per_minute = Keyword.get(opts, :words_per_minute, @words_per_minute)
     split_pattern = Keyword.get(opts, :split_pattern, @split_pattern)
-
+    text_format = Keyword.get(opts, :text_format, :text)
     words =
       string
       |> String.split(split_pattern, trim: true)
+      |> ignore_format_words(text_format)
       |> length
 
     minutes =

test/reading_time_test.exs

@@ -46,4 +46,36 @@ defmodule ReadingTimeTest do
                ) * long_text_multiplier
     end
   end
+
+  property "Markdown formatters get ignored" do
+    text = "
+    # This is a header1.
+
+    ## This is a header2.
+
+    This is also a header1.
+    ==
+
+    This is also a header2.
+    --
+
+    > This is a blockquote
+    >> This is a nested blockquote
+    >> # This is a header1 inside a blockquote
+
+    ---
+
+    - List1
+    + List2
+    * List3
+
+    ***
+
+    ___
+
+    "
+    actual_words = 37
+    assert ReadingTime.time(text, words_per_minute: 1, text_format: :markdown) == actual_words
+  end
+
 end