react-snowfall/src/utils.ts

A react component that creates a snowfall effect

/**
 * Enhanced random function, selects a random value between a minimum and maximum. If the values provided are both
 * integers then the number returned will be an integer, otherwise the return number will be a decimal.
 * @param min The minimum value
 * @param max The maximum value
 */
export function random(min: number, max: number): number {
  const randomNumber = Math.random() * (max - min + 1) + min

  if (!Number.isInteger(min) || !Number.isInteger(max)) {
    return randomNumber
  } else {
    return Math.floor(randomNumber)
  }
}

/**
 * Linear interpolation function to gradually step towards a target value
 * @param start The current value
 * @param end The target value
 * @param normal The rate of change between 0 and 1 (0 = no change, 1 = instant)
 */
export function lerp(start: number, end: number, normal: number) {
  return (1 - normal) * start + normal * end
}

/**
 * Selects a random item from an array of inputs.
 *
 * @param items The array of items to choose from
 * @returns A random item selected from the array
 */
export function randomElement<T>(items: T[]): T {
  const index = Math.floor(Math.random() * items.length)
  return items[index]
}

/**
 * Gets the height and width of the provided HTML element
 * @param element The html element to measure
 */
export function getSize(element?: HTMLElement | null) {
  if (!element) return { height: 0, width: 0 }

  return {
    height: element.offsetHeight,
    width: element.offsetWidth,
  }
}

/**
 * Store the value of PI * 2.
 *
 * This is so we can avoid calculating this value every time we draw a circle.
 */
export const twoPi = Math.PI * 2