https://github.com/nagilum/linqjs
Some LINQ functionality for JavaScript Array
https://github.com/nagilum/linqjs
Last synced: 3 months ago
JSON representation
Some LINQ functionality for JavaScript Array
- Host: GitHub
- URL: https://github.com/nagilum/linqjs
- Owner: nagilum
- License: mit
- Created: 2017-02-21T19:40:45.000Z (about 8 years ago)
- Default Branch: master
- Last Pushed: 2017-04-12T10:46:28.000Z (about 8 years ago)
- Last Synced: 2025-01-16T13:48:03.977Z (4 months ago)
- Language: JavaScript
- Size: 9.77 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# linqjs
Some LINQ functionality for JavaScript Array
Supplies the following functions for arrays:
* ```all```
* ```any```
* ```copy```
* ```distinct```
* ```first```
* ```orderBy```
* ```orderByDescending```
* ```select```
* ```skip```
* ```take```
* ```where```
Say you have the following array:
```js
let people = [
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' },
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' },
// Yes I know she is added twice, it's for the distinct() call!
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' }
];
```
## all
Determines whether all elements of a sequence satisfy a condition.
Param: ```Function predicate```
Returns: ```boolean```
---
Example:
```js
let allIsAlive = people.all(x => x.isAlive);
```
Will produce:
```js
false
```
## any
Determines whether any element of a sequence satisfies a condition.
Param: ```Function predicate```
Returns: ```boolean```
---
Example:
```js
let females = people.any(x => x.gender === 'F');
```
Will produce:
```js
true
```
## copy
Make an exact copy of the array, not a reference.
Param *none*
Returns: ```Array```
---
Example:
```js
let copiedList = people.copy();
```
Will produce:
```js
[
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' },
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' }
]
```
## distinct
Returns distinct elements from a sequence.
Param: *none*
Returns: ```Array```
---
Example:
```js
let distinctList = people.distinct();
```
Will produce:
```js
[
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' },
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' }
]
```
## first
Returns the first element of a sequence based on a predicate, or a null if the sequence contains no elements.
I've combined First(), FirstOrDefault(), Single(), and SingleOrDefault() into first(), and all "fails" just return a null.
Param: ```Function predicate```
Returns: ```Object```
---
Examples:
```js
let khan = people.first(x => x.name.endsWith('Khan'));
```
Will produce:
```js
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' }
```
---
```js
let obama = people.first();
```
Will produce:
```js
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' }
```
---
```js
let nonExisting = people.first(x => x.age === 100);
```
Will produce:
```js
null
```
## orderBy
Sorts the elements of a sequence in ascending order according to a key.
Param: ```string key```
Returns: ```Array```
---
Example:
```js
let alphabetically = people.orderBy('name');
```
Will produce:
```js
[
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' },
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' },
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' }
]
```
## orderByDescending
Sorts the elements of a sequence in descending order.
Param: ```string key```
Returns: ```Array```
---
Example:
```js
let unalphabetically = people.orderByDescending('name');
```
Will produce:
```js
[
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' },
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' },
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' }
]
```
## select
Projects each element of a sequence into a new form.
Param: ```Object map```
Returns: ```Array```
---
Example:
```js
let firstNamesAndGender = people.select({
firstName: x => x.name.substr(0, x.name.indexOf(' ')),
gender: x => x.gender === 'M' ? 'Male' : 'Female'
});
```
Will produce:
```js
[
{ firstName: 'Barack', gender: 'Male' },
{ firstName: 'Genghis', gender: 'Male' },
{ firstName: 'Britney', gender: 'Female' },
{ firstName: 'Ada', gender: 'Female' },
{ firstName: 'Ada', gender: 'Female' }
]
```
## skip
Bypasses a specified number of elements in a sequence and then returns the remaining elements.
Param: ```int number```
Returns: ```Array```
---
Example:
```js
let skipped = people.skip(2);
```
Will produce:
```js
[
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' },
{ name: 'Ada Lovelace', age: 36, isAlive: false, gender: 'F' }
]
```
## take
Returns a specified number of contiguous elements from the start of a sequence.
Param: ```int number```
Returns: ```Array```
---
Example:
```js
let taken = people.take(2);
```
Will produce:
```js
[
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' }
]
```
## where
Filters a sequence of values based on a predicate.
Param: ```Function predicate```
Returns: ```Array```
---
Example:
```js
let wheres = people.where(x => x.age > 50);
```
Will produce:
```js
[
{ name: 'Barack Obama', age: 55, isAlive: true, gender: 'M' },
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' }
]
```
## chains
You can chain multiple functions as they're prototypes of the Array object.
---
Examples:
```js
let names = people
.orderBy('name')
.skip(2)
.take(2)
.where(x => x.age < 40);
```
Will produce:
```js
[
{ name: 'Britney Spears', age: 35, isAlive: true, gender: 'F' }
]
```
---
```js
let otherPerson = people
.where(x => !x.isAlive &&
x.gender === 'M')
.first();
```
Will produce:
```js
{ name: 'Genghis Khan', age: 65, isAlive: false, gender: 'M' }
```