reanimated-math.macro

react-native-reanimated is amazing library for handling animations in react native.

Unfortunately nested function calls can get hard to read even if you are doing only simple arithmetic operations:

import { divide, multiply, sub } from 'react-native-reanimated'

function project(initialVelocity, decelerationRate) {
  return divide(
    multiply(divide(initialVelocity, 1000), decelerationRate),
    sub(1, decelerationRate),
  );
}

This babel.macro aims to simplify arithmetic over reanimated values.

Installation

yarn add reanimated-math.macro -D

If you are using older version of react-native than 0.56 you have to install and configure babel-plugin-macros as well.

Usage

import re from 'reanimated-math.macro'

function project(initialVelocity, decelerationRate) {
  return re(initialVelocity / 1000 * decelerationRate / (1 - decelerationRate))
}

or

import re from 'reanimated-math.macro'

function project(initialVelocity, decelerationRate) {
  return re`${initialVelocity} / 1000 * ${decelerationRate} / (1 - ${decelerationRate})`
}

reanimated	TaggedTemplateExpression	CallExpression
add(a, b, 1)	re`${a} + ${b} + 1`	re(a + b + 1)
sub(a, b, 1)	re`${a} - ${b} - 1`	re(a - b - 1)
multiply(a, b, 1)	re`${a} * ${b} * 1`	re(a * b * 1)
divide(a, b, 1)	re`${a} / ${b} / 1`	re(a / b / 1)
pow(a, b, 1)	re`${a} ** ${b} ** 1`	re(a ** b ** 1)
mod(a, b, 1)	re`${a} % ${b} % 1`	re(a % b % 1)
sqrt(a)	re`sqrt(${a})`	re(sqrt(a))
sin(a)	re`sin(${a})`	re(sin(a))
cos(a)	re`cos(${a})`	re(cos(a))
exp(a)	re`exp(${a})`	re(exp(a))
round(a)	re`round(${a})`	re(round(a))
floor(a)	re`floor(${a})`	re(floor(a))
ceil(a)	re`ceil(${a})`	re(ceil(a))
abs(a)	re`abs(${a})`	re(abs(a))
multiply(a, -1)	re`-${a}`	re(-a)