ObjectId

Blazing fast, cross-platform ObjectId implementation for the dart language!

Dart tests pub package License: MIT style: effective dart codecov

Why this package?

  • ๐Ÿš€ Fast.
  • ๐Ÿ“ฑ Cross-platform.
  • ๐Ÿงช Well tested.
  • ๐Ÿ“’ Fulfills bson ObjectId specification.
  • ๐Ÿ“ Documented.

Getting started.

  1. Depend on it.
dependencies:
  objectid: 1.1.0
  1. Play with it!
final id = ObjectId(); // That's all ๐Ÿ”ฅ๐Ÿ˜ฎ!
print(id.hexString);   // it's working! => 5f52c805df41c9df948e6135

Documentation

ObjectId()

Creates ObjectId instance based on current timestamp, process unique and counter. For more information take a look at ObjectId specification.

/// Creates ObjectId instance.
final id = ObjectId();
print(id.hexString); // => 5f52c805df41c9df948e6135

ObjectId.fromHexString(String hexString)

Creates ObjectId from hex string.

TIP ๐Ÿ’ก:
Can be helpful for mapping hex strings returned from API / mongodb.

/// Create ObjectId instance.
final id = ObjectId.fromHexString('5f52c805df41c9df948e6135');
print(id.hexString); // => 5f52c805df41c9df948e6135

final id2 = ObjectId.fromHexString(id.hexString);
print(id == id2); // => true

ObjectId.fromBytes(List bytes)

Creates ObjectId from bytes.

TIP ๐Ÿ’ก:
Sometimes we may want to save ObjectId representation to file, binary format is the best way to do so.

/// Create ObjectId instance.
final id = ObjectId.fromBytes([95, 82, 205, 121, 180, 195, 28, 88, 32, 47, 183, 78]);
print(id.hexString); // => 5f52cd79b4c31c58202fb74e

/// To retrive ObjectId bytes as [Uint8list] you can use `bytes` property.
print(id.bytes); // => [95, 82, 205, 121, 180, 195, 28, 88, 32, 47, 183, 78]

final id2 = ObjectId.fromBytes(id.bytes);
print(id == id2); // => true

ObjectId.fromValues(int millisecondsSinceEpoch, int processUnique, int counter)

Creates an ObjectId from the provided integer values.

/// Create ObjectId instance.
/// `hexString = 000000000000000000000000`
final zeroed = ObjectId.fromValues(0, 0, 0);

/// `hexString = ffffffff0000000000000000`
final withTimestamp = ObjectId.fromValues(0x3e7fffffc18, 0, 0); 

/// `hexString = 00000000ffffffffff000000`
final withProcessUnique = ObjectId.fromValues(0, 0xffffffffff, 0); 

/// `hexString = 000000000000000000ffffff`
final withCounter = ObjectId.fromValues(0, 0, 0xffffff);

/// `hexString = ffffffffffffffffffffffff`
final filled = ObjectId.fromValues(0x3e7fffffc18, 0xffffffffff, 0xffffff);

ObjectId.fromTimestamp(DateTime timestamp)

Creates ObjectId from provided timestamp.
Propably you do not want to use this constructor. It is mostly used for ObjectId comparisons or sorting.

Warning โš ๏ธ:
Only timestamp segment is set while the rest of the ObjectId is zeroed out.

/// Create ObjectId instance.
final id = ObjectId.fromTimestamp(DateTime.now());
print(id.hexString); // => 5f52d05e0000000000000000

bool operator ==

It is possible to compare ObjectIds instances by equality operator ==.
Comparison is based on ObjectId runtimeType and bytes.

int hashCode

Hashcode is calculated by dart implementation of Austin Appleby, MurmurHash2 algorithm; wich is for ObjectId almost 2 times faster ๐Ÿš€ than the commonly used Jenkins algorithm.

Property value will be generated only once (with the first read) and cached, what's strongly improves performance.

String hexString

Returns a 24-bit hex string representation of the ObjectId.

Property value will be generated only once (with the first read) and cached, what's strongly improves performance.

DateTime timestamp

Returns an accurate up to the second ObjectId generation time (timestamp).

Property value will be generated only once (with the first read) and cached, what's strongly improves performance.

Uint8List bytes

Returns a ObjectId bytes.


static bool isValid(String hexString)

Helper method that checks whether the provided hexString is a valid ObjectId.


Benchmark:

Benchmark hardware/software: Intel i7 3770k, 16GB RAM DDR3, Windows 10.

ObjectId() => 0.58338475488028056 us.
ObjectId.fromHexString(hexString) => 3.6401499394306052 us.
ObjectId.fromBytes(bytes) => 0.58338475488028056 us.
ObjectId.fromValues(millisecondsSinceEpoch, processUnique, counter) => 0.50956103355082625 us.
ObjectId.fromTimestamp(timestamp) => 0.47020163256147746 us.

Benchmark is available in the example app.

Libraries

objectid