build(deps-dev): apply updates
[poolifier.git] / src / utils.ts
1 import * as os from 'node:os'
2 import type {
3 MeasurementStatisticsRequirements,
4 WorkerChoiceStrategyOptions
5 } from './pools/selection-strategies/selection-strategies-types'
6 import type { KillBehavior } from './worker/worker-options'
7 import type { MeasurementStatistics } from './pools/worker'
8
9 /**
10 * Default task name.
11 */
12 export const DEFAULT_TASK_NAME = 'default'
13
14 /**
15 * An intentional empty function.
16 */
17 export const EMPTY_FUNCTION: () => void = Object.freeze(() => {
18 /* Intentionally empty */
19 })
20
21 /**
22 * Default worker choice strategy options.
23 */
24 export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
25 {
26 choiceRetries: 6,
27 runTime: { median: false },
28 waitTime: { median: false },
29 elu: { median: false }
30 }
31
32 /**
33 * Default measurement statistics requirements.
34 */
35 export const DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS: MeasurementStatisticsRequirements =
36 {
37 aggregate: false,
38 average: false,
39 median: false
40 }
41
42 /**
43 * Returns safe host OS optimized estimate of the default amount of parallelism a pool should use.
44 * Always returns a value greater than zero.
45 *
46 * @returns The host OS optimized maximum pool size.
47 */
48 export const availableParallelism = (): number => {
49 let availableParallelism = 1
50 try {
51 availableParallelism = os.availableParallelism()
52 } catch {
53 const numberOfCpus = os.cpus()
54 if (Array.isArray(numberOfCpus) && numberOfCpus.length > 0) {
55 availableParallelism = numberOfCpus.length
56 }
57 }
58 return availableParallelism
59 }
60
61 // /**
62 // * Computes the retry delay in milliseconds using an exponential back off algorithm.
63 // *
64 // * @param retryNumber - The number of retries that have already been attempted
65 // * @param maxDelayRatio - The maximum ratio of the delay that can be randomized
66 // * @returns Delay in milliseconds
67 // */
68 // export const exponentialDelay = (
69 // retryNumber = 0,
70 // maxDelayRatio = 0.2
71 // ): number => {
72 // const delay = Math.pow(2, retryNumber) * 100
73 // const randomSum = delay * maxDelayRatio * Math.random() // 0-(maxDelayRatio*100)% of the delay
74 // return delay + randomSum
75 // }
76
77 /**
78 * Computes the median of the given data set.
79 *
80 * @param dataSet - Data set.
81 * @returns The median of the given data set.
82 */
83 export const median = (dataSet: number[]): number => {
84 if (Array.isArray(dataSet) && dataSet.length === 0) {
85 return 0
86 }
87 if (Array.isArray(dataSet) && dataSet.length === 1) {
88 return dataSet[0]
89 }
90 const sortedDataSet = dataSet.slice().sort((a, b) => a - b)
91 return (
92 (sortedDataSet[(sortedDataSet.length - 1) >> 1] +
93 sortedDataSet[sortedDataSet.length >> 1]) /
94 2
95 )
96 }
97
98 /**
99 * Rounds the given number to the given scale.
100 * The rounding is done using the "round half away from zero" method.
101 *
102 * @param num - The number to round.
103 * @param scale - The scale to round to.
104 * @returns The rounded number.
105 */
106 export const round = (num: number, scale = 2): number => {
107 const rounder = Math.pow(10, scale)
108 return Math.round(num * rounder * (1 + Number.EPSILON)) / rounder
109 }
110
111 /**
112 * Is the given object a plain object?
113 *
114 * @param obj - The object to check.
115 * @returns `true` if the given object is a plain object, `false` otherwise.
116 */
117 export const isPlainObject = (obj: unknown): boolean =>
118 typeof obj === 'object' &&
119 obj !== null &&
120 obj?.constructor === Object &&
121 Object.prototype.toString.call(obj) === '[object Object]'
122
123 /**
124 * Detects whether the given value is a kill behavior or not.
125 *
126 * @typeParam KB - Which specific KillBehavior type to test against.
127 * @param killBehavior - Which kind of kill behavior to detect.
128 * @param value - Any value.
129 * @returns `true` if `value` was strictly equals to `killBehavior`, otherwise `false`.
130 */
131 export const isKillBehavior = <KB extends KillBehavior>(
132 killBehavior: KB,
133 value: unknown
134 ): value is KB => {
135 return value === killBehavior
136 }
137
138 /**
139 * Detects whether the given value is an asynchronous function or not.
140 *
141 * @param fn - Any value.
142 * @returns `true` if `fn` was an asynchronous function, otherwise `false`.
143 */
144 export const isAsyncFunction = (
145 fn: unknown
146 ): fn is (...args: unknown[]) => Promise<unknown> => {
147 return typeof fn === 'function' && fn.constructor.name === 'AsyncFunction'
148 }
149
150 /**
151 * Updates the given measurement statistics.
152 *
153 * @param measurementStatistics - The measurement statistics to update.
154 * @param measurementRequirements - The measurement statistics requirements.
155 * @param measurementValue - The measurement value.
156 * @param numberOfMeasurements - The number of measurements.
157 */
158 export const updateMeasurementStatistics = (
159 measurementStatistics: MeasurementStatistics,
160 measurementRequirements: MeasurementStatisticsRequirements,
161 measurementValue: number,
162 numberOfMeasurements: number
163 ): void => {
164 if (measurementRequirements.aggregate) {
165 measurementStatistics.aggregate =
166 (measurementStatistics.aggregate ?? 0) + measurementValue
167 measurementStatistics.minimum = Math.min(
168 measurementValue,
169 measurementStatistics.minimum ?? Infinity
170 )
171 measurementStatistics.maximum = Math.max(
172 measurementValue,
173 measurementStatistics.maximum ?? -Infinity
174 )
175 if (measurementRequirements.average && numberOfMeasurements !== 0) {
176 measurementStatistics.average =
177 measurementStatistics.aggregate / numberOfMeasurements
178 }
179 if (measurementRequirements.median && measurementValue != null) {
180 measurementStatistics.history.push(measurementValue)
181 measurementStatistics.median = median(measurementStatistics.history)
182 }
183 }
184 }