Sharp Collections - TypeScript LINQ library

Sharp Collections is new and modern LINQ library for TypeScript (can be used with JavaScript also). This is the library that you want to use for collections in TypeScript. It implements all of .NET Linq methods and some more (first, groupBy, groupJoin, orderBy, select, singleOrDefault, join, where etc.).

Features

• All .NET LINQ methods available and some more
• Deferred (lazy) execution
• Dictionary and HashSet with EqualityComparer support (same as in .NET)
• Intellisense friendly
• Implemented using generators and iterators
• ForOf cycle compatible
• Supports ES5 targeting

Playground

CodeSandbox playground

How to install

npm install sharp-collections

Example

import { Enumerable } from 'sharp-collections';

const data = [
  { name: 'Martin', sex: 'M', age: 28 },
  { name: 'Jane', sex: 'F', age: 27 },
  { name: 'Thomas', sex: 'M', age: 15 },
  { name: 'William', sex: 'M', age: 78 },
  { name: 'Kelly', sex: 'F', age: 30 },
];

const enumerable = Enumerable.from(data); // or List.from(data)

const adults = enumerable.where(x => x.age >= 18);
const adultsGroupedBySex = adults.groupBy(x => x.sex); // nothing is executed so far

// use any collection (Enumerable, List, Dictionary, ...) in ForOf cycle
for (const group of adultsGroupedBySex) {
  console.debug(`Sex: ${group.key}, count: ${group.count()}`);
}

// converts Enumerable to List
const adultsGroupedBySexList = adultsGroupedBySex.toList(); // or toReadOnlyList()

// converts Enumerable to JS Array
const adultsGroupedBySexArray = adultsGroupedBySex.toArray();

Collections

Collection	Read-Only alternative	Description
Enumerable	-	Represents a collection which supports a simple iteration.
List	ReadOnlyList	Represents a list of objects that can be accessed by index.
Dictionary	ReadOnlyDictionary	Represents a collection of keys and values. Values can be accessed by keys.
HashSet	ReadOnlyHashSet	Represents a set of values.
LinkedList	-	Represents a linked list of objects.
Stack	-	Represents a stack of objects.
Queue	-	Represents a queue of objects.

Implemented Linq methods

Method	Description
aggregate	Applies an accumulator function over a sequence.
all	Determines whether all elements of a sequence satisfy a condition.
any	Determines whether a sequence contains any elements.
append	Appends a value to the end of the sequence.
asEnumerable	Returns the sequence typed as an Enumerable.
asIndexed	Returns indexed sequence.
average	Computes the average of a sequence that are obtained by invoking a transform function on each element of the input sequence.
cast	Casts the elements to the specified type.
concat	Concatenates two sequences.
contains	Determines whether a sequence contains a specified element by using an equality comparer.
count	Returns a number that represents how many elements in the specified sequence satisfy a condition.
distinct	Returns distinct elements from a sequence.
distinctBy	Returns distinct elements from a sequence by using key selector to compare values.
elementAt	Returns the element at a specified index in a sequence.
elementAtOrDefault	Returns the element at a specified index in a sequence or a default value if the index is out of range.
elementsAt	Returns elements at a specified indexes in a sequence.
elementsAtRest	Returns elements at a specified indexes in a rest sequence.
except	Produces the set difference of two sequences.
first	Returns the first element of a sequence.
firstOrDefault	Returns the first element of a sequence, or undefined if the sequence contains no elements.
fullJoin	Performs a full outer join on two homogeneous sequences.
groupBy	Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.
groupJoin	Correlates the elements of two sequences based on equality of keys and groups the results.
intersect	Produces the set intersection of two sequences.
isEmpty	Determines whether the sequence is empty.
join	Correlates the elements of two sequences based on matching keys.
last	Returns the last element of a sequence that satisfies a specified condition.
lastOrDefault	Returns the last element of a sequence that satisfies a condition or undefined if no such element is found.
leftGroupJoin	Correlates the elements of two sequences based on equality of keys and groups the results.
leftJoin	Performs a left outer join on two homogeneous sequences.
max	Invokes a transform function on each element of a sequence and returns the maximum value.
maxBy	Returns the maximal elements of the given sequence, based on the given projection.
min	Invokes a transform function on each element of a sequence and returns the minimum value.
minBy	Returns the minimal elements of the given sequence, based on the given projection.
no	Determines whether no elements of a sequence satisfy a condition.
ofType	Filters the elements based on a specified type.
orderBy	Sorts the elements of a sequence according to a key.
orderByDescending	Sorts the elements of a sequence in descending order according to a key.
prepend	Adds a value to the beginning of the sequence.
reverse	Inverts the order of the elements in a sequence.
rightJoin	Performs a right outer join on two homogeneous sequences.
select	Projects each element of a sequence into a new form.
selectMany	Projects each element of a sequence and flattens the resulting sequences into one sequence.
sequenceEqual	Determines whether two sequences are equal by comparing the elements.
single	Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.
singleOrDefault	Returns the only element of a sequence that satisfies a specified condition or undefined if no such element exists; this method throws an exception if more than one element satisfies the condition.
skip	Bypasses a specified number of elements in a sequence and then returns the remaining elements.
skipWhile	Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.
slice	Returns subsequence of a sequence.
sum	Computes the sum of the sequence that are obtained by invoking a transform function on each element of the input sequence.
take	Returns a specified number of contiguous elements from the start of a sequence.
takeWhile	Returns elements from a sequence as long as a specified condition is true.
thenBy	Performs a subsequent ordering of the elements in a sequence according to a key.
thenByDescending	Performs a subsequent ordering of the elements in a sequence in descending order according to a key.
toArray	Converts sequence to an Array.
toReadOnlyDictionary	Converts sequence to a ReadOnlyDictionary.
toDictionary	Converts sequence to a Dictionary.
toHashSet	Converts sequence to a HashSet.
toLinkedList	Converts sequence to a LinkedList.
toList	Converts sequence to a List.
toLookup	Converts sequence to a Lookup.
toMap	Converts sequence to a Map.
toReadOnlyHashSet	Converts sequence to a ReadOnlyHashSet.
toReadOnlyList	Converts sequence to a ReadOnlyList.
toReadOnlyMap	Converts sequence to a ReadOnlyMap.
toReadOnlySet	Converts sequence to a ReadOnlySet.
toSet	Converts sequence to a Set.
union	Produces the set union of two sequences.
where	Filters a sequence of values based on a predicate.
zip	Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results.

License

MIT © Martin Volek