Quiver is a set of utility libraries for Dart that makes using many Dart libraries easier and more convenient, or adds additional functionality.
API Docs can be found here: http://google.github.io/quiver-dart/
Add Quiver to your project's pubspec.yaml file and run pub get.
We recommend the following version constraint:
dependencies:
quiver: '>=0.18.0<0.19.0'
Utilities for working with Futures, Streams and async computations.
FutureGroup is collection of Futures that signals when all its child futures
have completed. Allows adding new Futures as long as it hasn't completed yet.
Useful when async tasks can spwn new async tasks and you need to wait for all of
them to complete.
StreamRouter splits a Stream into mulltiple streams based on a set of
predicates.
CountdownTimer is a simple countdown timer that fires events in regular
increments.
doWhileAsync, reduceAsync and forEachAsync perform async computations on
the elements of on Iterables, waiting for the computation to complete before
processing the next element.
CreateTimer and CreateTimerPeriodic are typedefs that are useful for
passing Timer factories to classes and functions, increasing the testability of
code that depends on Timer.
Cache is a semi-persistent, asynchronously accessed, mapping of keys to
values. Caches are similar to Maps, except that the cache implementation might
store values in a remote system, so all operations are asynchronous, and caches
might have eviction policies.
MapCache is a Cache implementation backed by a Map.
listsEqual and mapsEqual check collections for equality.
Multimap is an associative collection that maps keys to collections of
values.
BiMap is a bidirectional map and provides an inverse view, allowing
lookup of key by value.
TreeSet is a balanced binary tree that offers a bidirectional iterator,
the ability to iterate from an arbitrary anchor, and 'nearest' search.
Optional is a way to represent optional values without allowing null.
firstNonNull returns its first non-null argument.
hashObjects, hash2, hash3, and hash4 generate high-quality hashCodes for
a list of objects, or 2, 3, or 4 arguments respectively.
visitDirectory is a recursive directory lister that conditionally recurses
into sub-directories based on the result of a handler function.
concat, count, cycle, enumerate, merge, partition, range, and
zip create, transform, or combine Iterables in different ways, similar to
Python's itertools.
min, max, and extent retreive the minimum and maximum elements from an
iterable.
getTypeName returns the name of a Type instance.
implements and classImplements determine if an instance or ClassMirror,
respectively, implement the interface represented by a Type instance. They
implement the behavior of is for mirrors, except for generics.
getMemberMirror searches though a ClassMirror and its class hierarchy for
a member. This makes up for the fact that ClassMirror.members doesn't
contain members from interfaces or superclasses.
Method wraps an InstanceMirror and Symbol to create a callable that invokes
a method on the instance. It in effect closurizes a method reflectively.
pattern.dart container utilities for work with Patterns and RegExps.
Glob implements glob patterns that are commonly used with filesystem paths.
matchesAny combines multiple Patterns into one, and allows for exclusions.
matchesFull returns true if a Pattern matches an entire String.
escapeRegex escapes special regex characters in a String so that it can be
used as a literal match inside of a RegExp.
Stream versions of quiver.iterables methods. Currently enumerate and
concat are supported.
StreamBuffer allows for the orderly reading of elements from a stream, such
as a socket.
isBlank checks if a string is null, empty or made of whitespace characters.
equalsIgnoreCase checks if two strings are equal, ignoring case.
compareIgnoreCase compares two strings, ignoring case.
flip flips the order of characters in a string.
nullToEmpty turns null to empty string, and returns non-empty strings
unchanged.
emptyToNull turns empty string to null, and returns non-empty strings
unchanged.
repeat concatenates a string to itself a given number of times, for example:
repeat('la ', 3) => 'la la la '
It can also repeat in reverse, for example:
repeat(' og', -3) => 'go go go '
loop allows you to loop through characters in a string starting and ending at
arbitrary indices. Out of bounds indices allow you to wrap around the string,
supporting a number of use-cases, including:
- Rotating:
loop('lohel', -3, 2) => 'hello' - Repeating, like
repeat, but with better character-level control, e.g.:loop('la ', 0, 8) => 'la la la' // no tailing space - Tailing:
loop('/path/to/some/file.txt', -3) => 'txt' - Reversing:
loop('top', 3, 0) => 'pot'
Clock provides points in time relative to the current point in time, for
example: now, 2 days ago, 4 weeks from now, etc. For tesability, use Clock
rather than other ways of accessing time, like new DateTime(), so that you
can use a fake time function in your tests to control time.
Now is a typedef for functions that return the current time in microseconds,
since Clock deals in DateTime which only have millisecond accuracy.
aMicrosecond, aMillisecond, aSecond, aMinute, anHour, aDay, and
aWeek are unit duration constants to allow writing for example:
aDayvs.const Duration(days: 1)aSecond * 30vs.const Duration(seconds: 30)
The Quiver testing libraries are intended to be used in testing code, not production code. It currently consists of fake implementations of some Quiver interfaces.
FakeAsync enables testing of units which depend upon timers and microtasks.
It supports fake advancements of time and the microtask queue, which cause fake
timers and microtasks to be processed. A Clock is provided from which to read
the current fake time. Faking synchronous or blocking time advancement is also
supported.
FakeTimer is a Timer that captures its duration and callback for use in tests.
assertCheckedMode asserts the current runtime has checked mode enabled.
FakeStopwatch is a Stopwatch that uses a provided now() function to get the
current time.