Looping over an array of objects and creating an array for each item with the same value at a certain index

I need to create an array that contains all the visits values if the date is the same without creating duplicate date arrays

const MOCK = {
        data: [
          {date: "Aug.03", name: "Nihal Pandit", visits: 3 },
          {date: "Aug.03", name: "Anthony Elias", visits: 3 },
          {date: "Aug.04", name: "Alex P.", visits: 2 },
          {date: "Aug.05", name: "Alex P.", visits: 3 },
          {date: "Aug.05", name: "Anthony Elias", visits: 3 },
        ]
     }

But im not sure of a method that lets you compare the values from one iteration to another when looping over an array. I think Array.reduce() might work, but I dont understand how to properly use reduce at this point.

I am looking for a result that looks like:

[["Aug.03", 3, 3], ["Aug.04",2],["Aug.05", 2, 3]

So I need an array for each date (the array should contain that date) and all the visit values from every object that contains that date.

let newArray = []
let visitCountValues = MOCK?.data?.map((item, idx)=> {
        let value = Object.values(item);
      if(value[0] === value[0]){
        newArray.push([value[0], value[1])
      }
        
      }) 

>Solution :

You can use reduce to group the array on one objectwithdate` as property.

And with object.entries you get the key ( date ) and value ( the array of entries ), then with map and Object.values, you can map and flat the object values into one array

const MOCK = {
        data: [
          {date: "Aug.03", name: "Nihal Pandit", visits: 3 },
          {date: "Aug.03", name: "Anthony Elias", visits: 3 },
          {date: "Aug.04", name: "Alex P.", visits: 2 },
          {date: "Aug.05", name: "Alex P.", visits: 3 },
          {date: "Aug.05", name: "Anthony Elias", visits: 3 },
        ]
     }
     
const dateGroups = Object.values(MOCK.data.reduce((acc, { date, visits }) => ({
  ...acc,
  [date]: [...(acc[date] || [date]), visits]
}), {}))

console.log(dateGroups)