src/utils.ts

   1 import os from 'node:os'
   2 import type {
   3   MeasurementStatisticsRequirements,
   4   WorkerChoiceStrategyOptions
   5 } from './pools/selection-strategies/selection-strategies-types'
   6
   7 /**
   8  * An intentional empty function.
   9  */
  10 export const EMPTY_FUNCTION: () => void = Object.freeze(() => {
  11   /* Intentionally empty */
  12 })
  13
  14 /**
  15  * Default worker choice strategy options.
  16  */
  17 export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
  18   {
  19     runTime: { median: false },
  20     waitTime: { median: false },
  21     elu: { median: false }
  22   }
  23
  24 /**
  25  * Default measurement statistics requirements.
  26  */
  27 export const DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS: MeasurementStatisticsRequirements =
  28   {
  29     aggregate: false,
  30     average: false,
  31     median: false
  32   }
  33
  34 /**
  35  * Returns safe host OS optimized estimate of the default amount of parallelism a pool should use.
  36  * Always returns a value greater than zero.
  37  *
  38  * @returns The host OS optimized maximum pool size.
  39  */
  40 export const availableParallelism = (): number => {
  41   let availableParallelism = 1
  42   try {
  43     availableParallelism = os.availableParallelism()
  44   } catch {
  45     const cpus = os.cpus()
  46     if (Array.isArray(cpus) && cpus.length > 0) {
  47       availableParallelism = cpus.length
  48     }
  49   }
  50   return availableParallelism
  51 }
  52
  53 /**
  54  * Computes the median of the given data set.
  55  *
  56  * @param dataSet - Data set.
  57  * @returns The median of the given data set.
  58  */
  59 export const median = (dataSet: number[]): number => {
  60   if (Array.isArray(dataSet) && dataSet.length === 0) {
  61     return 0
  62   }
  63   if (Array.isArray(dataSet) && dataSet.length === 1) {
  64     return dataSet[0]
  65   }
  66   const sortedDataSet = dataSet.slice().sort((a, b) => a - b)
  67   return (
  68     (sortedDataSet[(sortedDataSet.length - 1) >> 1] +
  69       sortedDataSet[sortedDataSet.length >> 1]) /
  70     2
  71   )
  72 }
  73
  74 /**
  75  * Rounds the given number to the given scale.
  76  *
  77  * @param num - The number to round.
  78  * @param scale - The scale to round to.
  79  * @returns The rounded number.
  80  */
  81 export const round = (num: number, scale = 2): number => {
  82   const rounder = Math.pow(10, scale)
  83   return Math.round(num * rounder * (1 + Number.EPSILON)) / rounder
  84 }
  85
  86 /**
  87  * Is the given object a plain object?
  88  *
  89  * @param obj - The object to check.
  90  * @returns `true` if the given object is a plain object, `false` otherwise.
  91  */
  92 export const isPlainObject = (obj: unknown): boolean =>
  93   typeof obj === 'object' &&
  94   obj !== null &&
  95   obj?.constructor === Object &&
  96   Object.prototype.toString.call(obj) === '[object Object]'