Cannot push into array from inside forEach loop

Question

Whenever I try to push into the pathItem array, the response is an empty array. What is happening?

        const categories = await Cars.find().distinct("bodytype");
        let pathItem = [];
        categories.forEach(async (element) => {
          const countQuery = await Cars.countDocuments({
            bodytype: element,
          });
          const numberOfPages = Math.ceil(countQuery / 12);
          for(let count=1; count<=numberOfPages; count++) {
          const carPath = {paths: { cartype: element, pages: count }}
            pathItem.push(carPath)
          }
        });
        console.log(pathItem) // this returns an empty array

Thanks a lot. That helped. Didn't know forEach does not wait for async calls. — canaryGrapher
– canaryGrapher, Commented Jun 21, 2021 at 18:39
@greyShader can you please add an answer to your question to help future question visitors? — programmerRaj
– programmerRaj, Commented Jun 21, 2021 at 21:45

canaryGrapher · Accepted Answer · 2021-06-22 17:25:27Z

4

This is what worked:

        const categories = await Cars.find().distinct("bodytype");
        let pathItem = [];
        for(let elements of categories) {
          const countQuery = await Cars.countDocuments({
            bodytype: element,
          });
          const numberOfPages = Math.ceil(countQuery / 12);
          for(let count=1; count<=numberOfPages; count++) {
          const carPath = {paths: { cartype: element, pages: count }}
            pathItem.push(carPath)
          }
        });
        console.log(pathItem) // this does not returns an empty array anymore

As Tushar mentioned, forEach does not wait for async calls, so Mongoose requests were not fulfilled before the forEach exited each loop.

answered Jun 22, 2021 at 17:25

canaryGrapher

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