HTML Code

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>mergeWith — fresh</title>
</head>
<body>
  <h1>Fresh object + concat</h1>
  <pre id="out"></pre>
  <script src="https://cdn.jsdelivr.net/npm/lodash@4.17.21/lodash.min.js"></script>
  <script>
    function concatArrays(objValue, srcValue) {
      if (_.isArray(objValue)) {
        return objValue.concat(srcValue);
      }
    }
    document.getElementById("out").textContent =
      JSON.stringify(_.mergeWith({}, { a: [1] }, { a: [2] }, concatArrays));
  </script>
</body>
</html>

Lines: 0 | Characters: 0

Live Preview Auto-refresh on Run

Lodash _.mergeWith — fresh + concat (Try It)