rnd package

Makes working with random values in Dart / Flutter easier:

  1. It provides an easy to access, global instance of Random.
  2. It adds helpful extension methods to Random.

Global instance

To make it easy to set up and propagate a Random instance throughout your app, the rnd package exposes a global instance via the rnd property. This makes generating a random value as simple as:

import 'package:rnd/rnd.dart';
rnd(10); // random double between 0-10
rnd.getBool(0.8); // 80% chance to get true

You can also get and set the seed for the global instance via rndSeed.

Extension methods on Random

Adds the following methods to all instances of Random. Read the docs for more info.

  • getInt(min, max, {curve}) // see "Curves" below
  • getDouble(min, max, {curve})
  • getBool(chance)
  • getBit(chance) // 0 or 1
  • getSign(chance) // -1 or 1
  • getDeg() // 0-360
  • getRad() // 0-2pi
  • getColor({...}) // see docs for params
  • getItem(list, {remove, curve})
  • shuffle(list, {copy}) // randomize list

It also defines a call method, which lets you get a random double value by calling a Random instance directly:

Random myRandom = new Random();
print(myRandom()); // double between 0-1
print(myRandom(10)); // 0-10
print(myRandom(5,10)); // 5-10

This pairs well with the global instance for quickly getting random values:

new Point(rnd(maxX), rnd(maxY))

Curves

The getDouble, getInt, and getItem methods support a curve param which transforms the value distribution. For example:

rnd.getInt(0, 100, curve: Curves.easeIn)

This would favor values nearer to 0, whereas easeOut would favor values nearer to 100. The included example app visualizes the effect of different curves.

Hue

The included Hue class provides named hue values for use with getColor. For example, Hue.green == 120.

rnd.getColor(hue: Hue.red); // red, green, blue, yellow, cyan, magenta

Libraries

rnd