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https://github.com/alexcambose/advmap
[...].map() that supports skip, limit, step and more
https://github.com/alexcambose/advmap
array improved javascript mapping object pagination prototype
Last synced: 5 days ago
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[...].map() that supports skip, limit, step and more
- Host: GitHub
- URL: https://github.com/alexcambose/advmap
- Owner: alexcambose
- License: mit
- Created: 2018-10-14T20:43:55.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2023-01-04T15:35:38.000Z (almost 2 years ago)
- Last Synced: 2024-05-21T04:21:14.849Z (6 months ago)
- Topics: array, improved, javascript, mapping, object, pagination, prototype
- Language: JavaScript
- Homepage:
- Size: 697 KB
- Stars: 3
- Watchers: 3
- Forks: 0
- Open Issues: 10
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# advmap
[](https://travis-ci.org/alexcambose/advmap)
[](https://coveralls.io/github/alexcambose/advmap?branch=master)
[](https://github.com/prettier/prettier)
[](https://github.com/Naereen/StrapDown.js/blob/master/LICENSE)
`[...].map()` that supports skip, limit, step and more
## Installation
As [npm](https://www.npmjs.com/package/advmap) package
```
npm i -S advmap
```
Importing the module. It will automatically add a method to the [array prototype](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/prototype).
```js
require('advmap');
// or
import 'advmap';
```
# Table of Contents
- [Configuration](#configuration)
- [Skip](#skip)
- [Limit](#limit)
- [Step](#step)
- [previousParamsCount](#previous-params)
- [nextParamsCount](#next-params)
- [Filtering](#filtering)
- [Examples](#examples)
## Configuration
### Skip
`skip` controls how many items to skip before returning results
Example:
```js
const array = [1, 2, 3, 4, 5].advmap(e => e, { skip: 2 });
console.log(array); // [3, 4, 5]
```
### Limit
`limit` controls the maximum number of items returned
Example:
```js
const array = [1, 2, 3, 4, 5].advmap(e => e, { limit: 2 });
console.log(array); // [1, 2]
```
it can be nicely combined with the `skip` property to create a pagination
```js
const array = [1, 2, 3, 4, 5].advmap(e => e, { limit: 2, skip: 2 });
console.log(array); // [3, 4]
```
### Step
controls the interval between two adjacent elements
```js
const array = [1, 2, 3, 4, 5].advmap(e => e, { step: 2 });
console.log(array); // [1, 3, 5]
// if step is bigger than the array length it returns only the first element
const array = [1, 2, 3, 4, 5].advmap(e => e, { step: 10 });
console.log(array); // [1]
```
it also provides an additional index parameter that is the actual array index that is being mapped
```js
[1, 2, 3, 4, 5].advmap((e, i, ii) => console.log(e, i, ii), { step: 2 });
/*
last parameter is where the item (e) is located in the array
[1, 0, 0]
[3, 1, 2]
[5, 2, 4]
*/
[1, 2, 3, 4, 5].advmap((e, i, ii) => console.log(e, i, ii), { step: 1 });
/*
If step is set to 1 (default) index parameters will be the same
[1, 0, 0]
[2, 1, 1]
[3, 2, 2]
[4, 3, 3]
[5, 4, 4]
*/
```
### Previous params
adds a number of fixed parameters to the `advmap` method, before the current element
```js
[1, 2, 3, 4, 5].advmap((p2, p1, e) => console.log(p2, p1, e), {
previousParamsCount: 2,
});
/*
[undefined, undefined, 1]
[undefined, 1, 2]
[1, 2, 3]
[2, 3, 4]
[3, 4, 5]
*/
```
elements that are outsite of the array are `undefined`
### Next params
adds a number of fixed parameters to the `advmap` method, after the current element
```js
[1, 2, 3, 4, 5].advmap((e, p1, p2) => console.log(e, p1, p2), {
nextParamsCount: 2,
});
/*
[1, 2, 3]
[2, 3, 4]
[3, 4, 5]
[4, 5, undefined]
[5, undefined, undefined]
*/
```
elements that are outsite of the array are `undefined`
### Previous and next params combined
```js
[1, 2, 3, 4, 5].advmap((p1, e, n2, n1) => console.log(p1, e, n2, n1), {
previousParamsCount: 1,
nextParamsCount: 2,
});
/*
[undefined, 1, 2, 3]
[1, 2, 3, 4]
[2, 3, 4, 5]
[3, 4, 5, undefined]
[4, 5, undefined, undefined]
*/
```
## Filtering
**advmap** provides an additional parameter that can be used to check if the current element, index etc.. respects a particular condition
```js
[1, 2, 3, 4, 5].advmap(e => e > 2 && e < 4, e => e + ' apples');
// [ '3 apples' ]
```
it also has all the arguments that the main map function has
```js
[0, 2, 3, 1, 5].advmap(
(p1, e, n1) => p1 > e && e < n1,
(p1, e) => e + ' is between two bigger numbers',
{
previousParamsCount: 1,
nextParamsCount: 1,
}
);
// [ '1 is between two bigger numbers' ]
```
## Examples
### Simple usage like the native `[].map` function
```js
const array = [1, 2, 3, 4].advmap(e => e + 1);
console.log(array); // [2,3,4,5]
```
Generate the next number in a [fibonacci sequence](https://en.wikipedia.org/wiki/Fibonacci_number)
```js
let array = [1, 1];
const nextNumber = () =>
array.advmap((p1, e, n1) => (p1 ? p1 + e : n1), {
previousParamsCount: 1,
nextParamsCount: 1,
});
array = nextNumber(); // [1, 2]
array = nextNumber(); // [2, 3]
array = nextNumber(); // [3, 5]
array = nextNumber(); // [5, 8]
array = nextNumber(); // [8, 13]
```
---
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---
## License
[MIT](LICENSE)