Merge pull request #786 from poolifier/worker-info

[poolifier.git] / src / utils.ts

diff --git a/src/utils.ts b/src/utils.ts
index 1d7f81d2d19fb41397a5ecdcbacde6d2d5076dd0..7ac4ab25db67446a49b2fc42a0f219c043d4af6f 100644 (file)
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,6 +1,8 @@
-import { CircularArray } from './circular-array'
-import type { WorkerChoiceStrategyOptions } from './pools/selection-strategies/selection-strategies-types'
-import type { TasksUsage } from './pools/worker'
+import os from 'node:os'
+import type {
+  MeasurementStatisticsRequirements,
+  WorkerChoiceStrategyOptions
+} from './pools/selection-strategies/selection-strategies-types'
 
 /**
  * An intentional empty function.
@@ -10,40 +12,86 @@ export const EMPTY_FUNCTION: () => void = Object.freeze(() => {
 })
 
 /**
- * Initial tasks usage statistics.
+ * Default worker choice strategy options.
  */
-export const INITIAL_TASKS_USAGE: TasksUsage = {
-  run: 0,
-  running: 0,
-  runTime: 0,
-  runTimeHistory: new CircularArray(),
-  avgRunTime: 0,
-  medRunTime: 0,
-  error: 0
-}
+export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
+  {
+    runTime: { median: false },
+    waitTime: { median: false },
+    elu: { median: false }
+  }
 
 /**
- * Default worker choice strategy options.
+ * Default measurement statistics requirements.
  */
-export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
+export const DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS: MeasurementStatisticsRequirements =
   {
-    medRunTime: false
+    aggregate: false,
+    average: false,
+    median: false
+  }
+
+/**
+ * Returns safe host OS optimized estimate of the default amount of parallelism a pool should use.
+ * Always returns a value greater than zero.
+ *
+ * @returns The host OS optimized maximum pool size.
+ */
+export const availableParallelism = (): number => {
+  let availableParallelism = 1
+  try {
+    availableParallelism = os.availableParallelism()
+  } catch {
+    const cpus = os.cpus()
+    if (Array.isArray(cpus) && cpus.length > 0) {
+      availableParallelism = cpus.length
+    }
   }
+  return availableParallelism
+}
 
 /**
- * Compute the median of the given data set.
+ * Computes 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 === 0) {
+    return 0
+  }
   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
+  return (
+    (sortedDataSet[(sortedDataSet.length - 1) >> 1] +
+      sortedDataSet[sortedDataSet.length >> 1]) /
+    2
+  )
+}
+
+/**
+ * Rounds the given number to the given scale.
+ * The rounding is done using the "round half away from zero" method.
+ *
+ * @param num - The number to round.
+ * @param scale - The scale to round to.
+ * @returns The rounded number.
+ */
+export const round = (num: number, scale = 2): number => {
+  const rounder = Math.pow(10, scale)
+  return Math.round(num * rounder * (1 + Number.EPSILON)) / rounder
 }
+
+/**
+ * Is the given object a plain object?
+ *
+ * @param obj - The object to check.
+ * @returns `true` if the given object is a plain object, `false` otherwise.
+ */
+export const isPlainObject = (obj: unknown): boolean =>
+  typeof obj === 'object' &&
+  obj !== null &&
+  obj?.constructor === Object &&
+  Object.prototype.toString.call(obj) === '[object Object]'