@calipsa/video-utils/src/utils/downsampleArray.ts

Video utilities

import { range } from 'lodash'

export default <T>(arr: readonly T[], newSize: number) => {
  if (newSize < 1) {
    return []
  }

  if (arr.length <= newSize) {
    return arr.slice()
  }

  if (newSize === 1) {
    const midIndex = arr.length - 1 >> 1
    return [arr[midIndex]]
  }

  const ratio = (arr.length - 1) / (newSize - 1)
  const indices = range(newSize).map(i => Math.round(i * ratio))
  return indices.map(i => arr[i])
}