Easing

The Easing module implements common easing functions. This module is used by Animated.timing() to convey physically believable motion in animations.
You can find a visualization of some common easing functions at http://easings.net/

The Easing module provides several predefined animations through the following methods:
• back provides a simple animation where the object goes slightly back before moving forward
• bounce provides a bouncing animation
• ease provides a simple inertial animation
• elastic provides a simple spring interaction

Three standard easing functions are provided:
The poly function can be used to implement quartic, quintic, and other higher power functions.

Additional mathematical functions are provided by the following methods:
• bezier provides a cubic bezier curve
• circle provides a circular function
• sin provides a sinusoidal function
• exp provides an exponential function
The following helpers are used to modify other easing functions.
• in runs an easing function forwards
• inOut makes any easing function symmetrical
• out runs an easing function backwards

Reference

static step0(n)
A stepping function, returns 1 for any positive value of n.

static step1(n)
A stepping function, returns 1 if n is greater than or equal to 1.

static linear(t)
A linear function, f(t) = t. Position correlates to elapsed time one to one.

static ease(t)
A simple inertial interaction, similar to an object slowly accelerating to speed.

A quadratic function, f(t) = t * t. Position equals the square of elapsed time.

static cubic(t)
A cubic function, f(t) = t * t * t. Position equals the cube of elapsed time.

static poly(n)
A power function. Position is equal to the Nth power of elapsed time.

static sin(t)
A sinusoidal function.

static circle(t)
A circular function.

static exp(t)
An exponential function.

static elastic(bounciness)
A simple elastic interaction, similar to a spring oscillating back and forth.
Default bounciness is 1, which overshoots a little bit once. 0 bounciness doesn't overshoot at all, and bounciness of N > 1 will overshoot about N times.

static back(s)
Use with Animated.parallel() to create a simple effect where the object animates back slightly as the animation starts.

static bounce(t)
Provides a simple bouncing effect.

static bezier(x1, y1, x2, y2)
Provides a cubic bezier curve, equivalent to CSS Transitions' transition-timing-function.
A useful tool to visualize cubic bezier curves can be found at http://cubic-bezier.com/