Display Paginated column index in reverse order

May 24, 2023

I’m facing a problem during the display of paginated data. Default the program will display 5 rows per page and during the column index it is displaying the row no starting from 1, and then on the second page the row no will start from 6.

idx: 1 | name: John
idx: 2 | name: Doe
idx: 3 | name: John
idx: 4 | name: Doe
idx: 5 | name: John

page = 2:

idx: 6 | name: Tim
idx: 7 | name: John
idx: 8 | name: Doe
idx: 9 | name: John
idx: 10 | name: Doe

Code:

const names = [
    "John",
    "Doe",
    "John",
    "Doe",
    "John",
    "Tim",
    "John",
    "Doe",
    "John",
    "Doe",
];

let page = 1;
let limit = 5;
let totalCount = names.length || 0;

function pagination(array, page, limit) {
    return array.slice((page - 1) * limit, page * limit);
}

const newArray = pagination(names, page, limit);

newArray.forEach((item, index) => {
    const idx = (page - 1) * limit + (index + 1);
    console.log("idx:", idx, "|", "name:", item);
});

When I change page no to 2, then it will display starting row no 6 on the second page.

But the problem is I want to display the row indexing in reverse order something like this:
the first row should display the index as 10, and on the second page, the index starts from 5. How can I achieve this and what is the formula for this?

idx: 10 | name: John
idx: 9 | name: Doe
idx: 8 | name: John
idx: 7 | name: Doe
idx: 6 | name: John

page = 2:

idx: 5 | name: Tim
idx: 4 | name: John
idx: 3 | name: Doe
idx: 2 | name: John
idx: 1 | name: Doe

>Solution :

You need to change only on idx varible calculation. hope it’s useful for you.

const names = [
  "John",
  "Doe",
  "John",
  "Doe",
  "John",
  "Tim",
  "John",
  "Doe",
  "John",
  "Doe",
];

let page = 1;
let limit = 5;
let totalCount = names.length || 0;

function pagination(array, page, limit) {
  return array.slice((page - 1) * limit, page * limit);
}

const newArray = pagination(names, page, limit);

newArray.forEach((item, index) => {
  const idx = totalCount - ((page - 1) * limit) - index;
  console.log("idx:", idx, "|", "name:", item);
});