Steps for building a personalized pipe to paginate data within Angular

Question

Steps for building a personalized pipe to paginate data within Angular

Creating a custom pagination pipe in Angular to filter data and display 100 records per page. For example, page 1 shows records 0-99, page 2 shows records 100-199, and so on.

The data.json file contains an array with 1300 objects. Sample data: https://pastebin.com/7V2DNj8W

Each object in the data looks like this:

{
    "location_type": "KAUPPAKESKUS",
    "postalcode": "2770",
    "availability": "24 H AUKIOLO",
    "location": "ESPOONTORI /INSTRUMENTARIUM",
    "municipality": "ESPOO",
    "target_address": "KAMREERINTIE 3",
    "availability_details": "",
    "coordinates_lon": "24.656450",
    "coordinates_lat": "60.203750"
}

The pagination.pipe.ts code snippet ensures that the correct records are displayed on each page based on the provided parameters.

// Code snippet omitted for brevity

When navigating to different URLs such as http://localhost:4200/page/0 and http://localhost:4200/page/1, the expected records should be displayed in the console and in the corresponding table.

Correction:

This is the content of page.component.html:

// Code snippet omitted for brevity

and here is page.component.ts:

// Code snippet omitted for brevity

angular typescript

Answer 1

Answer №1

There appears to be a potential issue with the "index" logic.

let index = 0;

...

if (index >= (page * per_page) && index < (page + 1) * per_page) {

If the index consistently remains at zero, then- page 0:

if (0 >= (0 * 100) && 0 < (0 + 1) * 100) // true, list will be generated

page 1:

if (0 >= (1 * 100) && 0 < (1 + 1) * 100) // false, (0 >= (1 * 100) will never evaluate to true

pages greater than 1:

// outcome will be similar to page 1

You may consider setting your index to begin at page * page_size - 1

Answer 2

There appears to be a potential issue with the "index" logic.

let index = 0;

...

if (index >= (page * per_page) && index < (page + 1) * per_page) {

If the index consistently remains at zero, then- page 0:

if (0 >= (0 * 100) && 0 < (0 + 1) * 100) // true, list will be generated

page 1:

if (0 >= (1 * 100) && 0 < (1 + 1) * 100) // false, (0 >= (1 * 100) will never evaluate to true

pages greater than 1:

// outcome will be similar to page 1

You may consider setting your index to begin at page * page_size - 1

Answer 3

Answer №2

The main issue at hand is that the variable page is currently defined as a type of string instead of number. This causes an error in the calculation of the expression when the value of page is 1, resulting in an incorrect output:

let lastIndex = page + 1 // displays 11 instead of 2

To resolve this issue, I updated the variable page to be of type number as follows:

ngOnInit() {
    this.route.params.subscribe(parameters => {
        this.page = +parameters.page;
    })
}

Additionally, the statement index++ must be placed outside of the if condition within the loop to ensure that the index is incremented with each iteration:

for (let atm of atms) {
  if (index >= (page * per_page) && index < (page + 1) * per_page) {
    data.push(atm);
  }
  index++;
}

Answer 4

The main issue at hand is that the variable page is currently defined as a type of string instead of number. This causes an error in the calculation of the expression when the value of page is 1, resulting in an incorrect output:

let lastIndex = page + 1 // displays 11 instead of 2

To resolve this issue, I updated the variable page to be of type number as follows:

ngOnInit() {
    this.route.params.subscribe(parameters => {
        this.page = +parameters.page;
    })
}

Additionally, the statement index++ must be placed outside of the if condition within the loop to ensure that the index is incremented with each iteration:

for (let atm of atms) {
  if (index >= (page * per_page) && index < (page + 1) * per_page) {
    data.push(atm);
  }
  index++;
}

Steps for building a personalized pipe to paginate data within Angular

Answer №1

Answer №2

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