JS: Chunk an array in a pattern (Initial implementation of https://github.com/srph/chunk-pattern)

chunk-pattern.js

/* @flow */

/**
 * Chunks an array in a specific pattern
 * @example chunkPattern(['haha', 'haha', 'haha', 'haha', 'haha', 'haha', 'haha', 'haha', 'haha'], [2, 3])
 * @return Array<Array<*>>
 */
function chunkPattern(array: Array<*>, pattern: Array<number>): Array<Array<*>> {
  const result: Array<Array<*>> = []

  let patternIndex: number = 0
  let patternCount: number = 0

  array.forEach((item, i) => {
    if (patternCount === 0) {
      result.push([])
      patternIndex = clampReset(patternIndex + 1, 0, pattern.length - 1)
      patternCount = pattern[patternIndex]
    }

    const last = result[result.length - 1]
    last.push(item)
    patternCount--
  })

  return result
}

/**
 * If value exceeds min, assigns value to max.
 * If value exceeds max, assigns value to min.
 * @return {number}
 */
function clampReset(value: number, min: number, max: number): number {
  if (value < min) {
    return min
  }

  if (value > max) {
    return max
  }

  return value
}

console.log(
  chunkPattern(['haha', 'haha', 'haha', 'haha', 'haha', 'haha', 'haha', 'haha', 'haha'], [2, 3])
)