Duplicate TOC entries when compiling MD files from several JSONs in single JS

[pharaoh1st]

fs.readdirSync("./").filter(f => f.toLowerCase().endsWith(".json")).forEach(function(markdownJson) {
  markdownInclude.compileFiles(markdownJson).then(function () {
    console.info(markdownJson + ' have been built successfully');
  })
});

Example:
There are 3 JSON files in the directory with different files for compilation. But some of the MD files are reused in different compiled MD files.

1st.md content

#include my.md

2nd.md content

#include my.md
#include my2.md

3rd.md content

#include my.md
#include my3.md

my2.md content

some content about my2.
#include my3.md

every MD file has it's own unique Heading with !heading tag for inclusion into TOC.