docs: enhance documentation and update changelog entries

[poolifier.git] / src / utils.ts

import { CircularArray } from './circular-array'
import type { WorkerChoiceStrategyOptions } from './pools/selection-strategies/selection-strategies-types'
import type { TasksUsage } from './pools/worker'

/**
 * An intentional empty function.
 */
export const EMPTY_FUNCTION: () => void = Object.freeze(() => {
  /* Intentionally empty */
})

/**
 * Initial tasks usage statistics.
 */
export const INITIAL_TASKS_USAGE: TasksUsage = {
  run: 0,
  running: 0,
  runTime: 0,
  runTimeHistory: new CircularArray(),
  avgRunTime: 0,
  medRunTime: 0,
  error: 0
}

/**
 * Default worker choice strategy options.
 */
export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
  {
    medRunTime: false
  }

/**
 * Compute the median of the given data set.
 *
 * @param dataSet - Data set.
 * @returns The median of the given data set.
 */
export const median = (dataSet: number[]): number => {
  if (Array.isArray(dataSet) && dataSet.length === 1) {
    return dataSet[0]
  }
  const sortedDataSet = dataSet.slice().sort((a, b) => a - b)
  const middleIndex = Math.floor(sortedDataSet.length / 2)
  if (sortedDataSet.length % 2 === 0) {
    return sortedDataSet[middleIndex / 2]
  }
  return (sortedDataSet[middleIndex - 1] + sortedDataSet[middleIndex]) / 2
}