How can I loop and push an array into an array?

Question

I'm trying to simplify my codes by using loop

let tmpD = [];
let tmpS0 = [];
let tmpS1 = [];
let tmpS2 = [];

signed = doctors.doc(tmpD[0].key).collection('schedule').get();
signed.then(function(ss){
  ss.forEach(function(schedule){
    tmpS0.push(schedule.data());
  });
  console.log(tmpS0)
});
signed = doctors.doc(tmpD[1].key).collection('schedule').get();
signed.then(function(ss){
  ss.forEach(function(schedule){
    tmpS1.push(schedule.data());
  });
  console.log(tmpS1)
});
signed = doctors.doc(tmpD[2].key).collection('schedule').get();
signed.then(function(ss){
  ss.forEach(function(schedule){
    tmpS2.push(schedule.data());
  });
  console.log(tmpS2)
});

I've tried using for loop like for(var i = 0; i < tmpD.length; i++) above the first signed and pushed the data to tmpS and it turns out it pushed everything to a single array. I also tried pushing the array to tmpS[i] but it caused an error.

Answer 1

You could create a 2D array of tmpS0 , tmpS1 etc and update them based on the index:

let tmpD = [];
let tmpS0 = [];
let tmpS1 = [];
let tmpS2 = [];

let tmps = [tmpS0, tmpS1, tmpS2];

tmpD.forEach(({ key }, i) => {
  const signed = doctors.doc(key).collection('schedule').get();
  signed.then(function(ss) {
    ss.forEach(function(schedule) {
      tmps[i].push(schedule.data());
    });
    console.log(tmps[i])
  });
})

Update:

If the variables are dynamic, you can just create the tmpS array and keep pushing to it based on the index of tmpD array:

let tmpD = [];
let tmpS = []; // 2D array

tmpD.forEach(({ key }, i) => {
  const signed = doctors.doc(key).collection('schedule').get();
  signed.then(function(ss) {
    tmpS[i] = tmpS[i] || []; // initialize the inner array

    ss.forEach(function(schedule) {
      tmpS[i].push(schedule.data());
    });

    console.log(tmpS[i])
  });
})

// tmpS will have same number of inner arrays as tmpD.length
console.log(tmpS)