Pass 1 sync and 1 async variables to next async function

I am using mongodb realm with a simple custom query function to return DB data

  function mongo(data) {
    return fetch(
      apiurl,
    {
      method: "POST",
       headers: {
          "Content-Type": "application/json",
       },
        body: JSON.stringify(data),
       }
    )
    .then((response) => {
      return response.json();
    })
    .then((data) => {
      console.log("Success:", data);
      return data;
    })
    .catch((error) => {
      console.error("Error:", error);
    });
  }

  mongo({
    collection: "metadata",
    action: "find",
    criteria: { query: {}},
  }).then((metadata) => {
    for (var i = 0; i < metadata.length; i++) {
      var oneMeta= metadata[i];
      var subjectName = oneMeta.name;
      var subjectCode = oneMeta.code;
      var blockHTML =
        `<div>
        <span class="badge badge-danger">` + subjectName + `</span>
        <span class="badge badge-dark">` + subjectCode + `</span>
        </div>`;
      var oneSubject = document.createElement("div");
      oneSubject.id = "sub_"+subjectCode 
      oneSubject.innerHTML = blockHTML;
      subjectOutput.appendChild(oneSubject);
    }
  });

I was trying to do another mongo({collection: "actualData", action: "count", criteria: { query: {subjectId: XXX}}}) query for each metadata where XXX would be subjectCode from metadata[i]

The goal is to append another <span>count</span> to the DIV created above using its id, where the count is the result of the second mongo function.

I was only able to do it without looping metadata.length

I need to do the next function for every time in the loop, while using i and metadata

Any help appreciated!

Just map your metadata to an array of mongo promises, await all of them, then the count result will be in the same position of the array:

mongo({
    collection: "metadata",
    action: "find",
    criteria: { query: {}},
  }).then(async (metadata) => {
    const counts = await Promise.all(metadata.map((oneMeta) => {
      return mongo({collection: "actualData", action: "count", criteria: { query: {subjectId: oneMeta.subjectCode}}});
    }));
    for (let i = 0; i < metadata.length; i++) {
      const count = counts[i];
      const oneMeta = metadata[i];
      const subjectName = oneMeta.name;
      const subjectCode = oneMeta.code;
      var blockHTML =
          `<div>
          <span class="badge badge-danger">` + subjectName + `</span>
          <span class="badge badge-dark">` + subjectCode + `</span>
          <span class="badge badge-dark">` + count + `</span>
          </div>`;
      var oneSubject = document.createElement("div");
      oneSubject.id = "sub_"+subjectCode 
      oneSubject.innerHTML = blockHTML;
      subjectOutput.appendChild(oneSubject);
    }
})