How to use the leasot.isExtSupported function in leasot

testFiles.forEach(file => {
    // skip source files from node_modules
    // https://github.com/mikeerickson/todo-webpack-plugin/issues/21
    if (file.match(/node_modules/g)) {
      return;
    }

    if (options.skipUnsupported) {
      if (!leasot.isExtSupported(path.extname(file))) {
        return;
      }
    }

    const todo = leasot.parse({
      ext: path.extname(file),
      content: fs.readFileSync(file, 'utf8'),
      fileName: file,
      customTags: options.tags,
      reporter: options.reporter,
      withInlineFiles: options.withInlineFiles
    });
    todos = todos.concat(todo);
  });

processString(content, relativePath) {
		if (this.enabled) {
			const fileExtension = path.extname(relativePath);
			if (leasot.isExtSupported(fileExtension)) {
				this._markers.push(leasot.parse({
					ext: fileExtension, 
					content: content, 
					fileName: relativePath, 
					customTags: this.kinds
				}));
			} else {
				this._exceptions.push(fileExtension);
			}
		}
		return content;
	}