react-native-realistic-deck-swiper/helpers.js

Deck swiper with realistic physics.

export function getInitialOffsets(offsetAngleMin, offsetAngleMax, deckSize) {
  if(typeof offsetAngleMin === 'undefined' || typeof offsetAngleMax === 'undefined' || typeof deckSize === 'undefined') {
    throw new Error('Missing arguments.')
  }
  if(!Number.isInteger(offsetAngleMin)|| !Number.isInteger(offsetAngleMax) || !Number.isInteger(deckSize)) {
    throw new Error('All arguments must be integers')
  }
  if(offsetAngleMin >= offsetAngleMax) {
    throw new Error('offsetAngleMin must be less than offsetAngleMax.')
  }
  if(deckSize < 2) {
    throw new Error('deckSize must be two or more.')
  }
  if(offsetAngleMax - offsetAngleMin + 1 < deckSize) {
    throw new Error('Min Max integer range must be greater than or equal to deckSize.')
  }
  let offsets = []
  //TODO
  //O(n*n*log(n))
  //does initial offsets have to be random?
  for (let i = 0; i < deckSize; i++) {
    offsets.push(getUniqueElement(offsets, offsetAngleMin, offsetAngleMax))
  }
  return offsets
}

//TODO
//problems: uniques <= range(min, max)
//if deckSize > range(min, max) there's not enough uniques
//sol: add minimumOffsetDelta, calc and throw error if deckSize too big
export function updateCardOffsets(offsets, offsetAngleMin, offsetAngleMax) {
  if(!offsets || !offsetAngleMin || !offsetAngleMax) {
    throw new Error('Missing arguments.')
  }
  if(!Array.isArray(offsets) || !Number.isInteger(offsetAngleMin) || !Number.isInteger(offsetAngleMax)) {
    throw new Error('Invalid argument type, expected (offsets = array, offsetAngleMin = integer, offsetAngleMax = integer.')
  }
  if(offsetAngleMin >= offsetAngleMax) {
    throw new Error('offsetAngleMin must be less than offsetAngleMax.')
  }
  return [...offsets.slice(1), getUniqueElement(offsets.slice(1), offsetAngleMin, offsetAngleMax)]
}

export function getInterpolatedRotation(deg, rotation) {
  if(typeof deg === 'undefined' || typeof rotation === 'undefined' || !Number.isInteger(deg) || !Number.isInteger(rotation)) {
    throw new Error(`Invalid arguments, expected (deg = integer, rotation = integer.`)
  }
  return deg * rotation / 360
}


function getRandomIntInclusive(min, max) {
  min = Math.ceil(min);
  max = Math.floor(max);
  return Math.floor(Math.random() * (max - min + 1)) + min;
}
function getUniqueElement(array, min, max) {
  let set = new Set(range(min, max, 1))
  array.forEach(value => set.delete(value))
  const uniques = Array.from(set)
  let value = uniques[getRandomIntInclusive(0, uniques.length - 1)]
  return value
}

function range(start, end, step = 1) {
  const len = Math.floor((end - start) / step) + 1
  return Array(len).fill().map((_, idx) => start + (idx * step))
}