cimulative key and value using forEach

I want to merge each key and value each time I treverse elements, but whenever I pass for loop, the overwrite the newest new instead of merge the new elments = old elements + new elements here is my forEach:

        let ff = {};
        let tmp_ff = {};

        this.choosen_products.forEach((element, index, array) => {
            //q_p1_fullname
            let tmp1 = "q_p"+(index+1)+"_fullname"; //each time, tmp1 key are different
            let tmp2 = "q_p"+(index+1)+"_code";
            let tmp3 = "q_p"+(index+1)+"_category";
            let tmp4 = "q_p"+(index+1)+"_cost";
            let tmp5 = "q_p"+(index+1)+"_margin";
            let tmp6 = "q_p"+(index+1)+"_sell";
            console.log(element.p_fullname + " " + element.p_category + "       "  +  tmp1);
            /*
            ff.this.tmp1 = element.p_fullname, //I try this, no help
            ff.this.tmp2 = element.p_code,
            ff.this.tmp3 = element.p_category,
            ff.this.tmp4 = element.p_cost,
            ff.this.tmp5 = element.p_margin,
            ff.this.tmp6 = element.p_sell,
            */
            tmp_ff = {
                [tmp1]: element.p_fullname, //works but only the most recent loop, how to merged??
                [tmp2]: element.p_code,
                [tmp3]: element.p_category,
                [tmp4]: element.p_cost,
                [tmp5]: element.p_margin,
                [tmp6]: element.p_sell,
            };
            let merged = { tmp_ff, ff }; 

            Object.keys(tmp_ff).forEach(key => {
                console.log("[previewBtn-choosen_products2]" + key, tmp_ff[key]); //not cimulative
            });


            console.log("[previewBtn-choosen_products2]        " ); // 100, 200, 300
            console.log(index); // 0, 1, 2
            console.log(array); // same myArray object 3 times
            bodyData.push(element);

            console.log("[previewBtn-choosen_products2]" + Object.keys(merged).tmp1);
        });`

I want these 6 keys and elements sum-up, which means the second forEach loop, total the Object has 12 and 18 key and value etc. Now only the newest one exist, I try to do

merged = { tmp_ff, ff }; 

but no specific help yet, I see merged has only length of 2…

My final result want to be like this:

tmp_ff = {
                    q_p1_fullname: element.p_fullname,
                    q_p1_code: element.p_code,
                    q_p1_category: element.p_category,
                    q_p1_cost: element.p_cost,
                    q_p1_margin: element.p_margin,
                    q_p1_sell: element.p_sell,
                    q_p2_fullname: element.p_fullname,
                    q_p2_code: element.p_code,
                    q_p2_category: element.p_category,
                    q_p2_cost: element.p_cost,
                    q_p2_margin: element.p_margin,
                    q_p2_sell: element.p_sell,

                };

>Solution :

without data I can’t create an example, but this should build your dictionary in one go:

const tmp_ff = Object.fromEntries(
  this.choosen_products.flatMap((element, index) => [
    [`q_p${index + 1}_fullname`, element.p_fullname],
    [`q_p${index + 1}_code`, element.p_code],
    [`q_p${index + 1}_category`, element.p_category],
    [`q_p${index + 1}_cost`, element.p_cost],
    [`q_p${index + 1}_margin`, element.p_margin],
    [`q_p${index + 1}_sell`, element.p_sell],
  ])
);

console.log(tmp_ff);

I just don’t find this data structure useful. It’s definitely harder to work with than the array.