Implementation:Webdriverio Webdriverio MSPO Aggregator

Knowledge Sources	Webdriverio_Webdriverio
Domains	Mobile_Testing, Performance_Optimization
Last Updated	2026-02-12 00:00 GMT

Overview

The MSPO Aggregator module collects selector performance data from all worker processes and generates consolidated CLI and markdown reports.

Description

This module provides the aggregateSelectorPerformanceData function which reads per-worker JSON data files, merges them, groups entries by device name, and produces structured output. It generates JSON reports unconditionally, and optionally produces CLI terminal output and markdown reports based on configuration flags. The getDeviceName helper extracts device identifiers from various capability structures (standard, multiremote, and W3C).

Usage

This module is called by AppiumLauncher.onComplete() at the end of a test run to aggregate performance data collected by individual worker processes. It should not typically be called directly by end users.

Code Reference

Source Location

Repository: Webdriverio_Webdriverio
File: packages/wdio-appium-service/src/mobileSelectorPerformanceOptimizer/aggregator.ts
Lines: 140-494

Signature

export async function aggregateSelectorPerformanceData(
    capabilities: Capabilities.TestrunnerCapabilities | Capabilities.ResolvedTestrunnerCapabilities,
    maxLineLength: number,
    writeFn?: (message: string) => void,
    reportDirectory?: string,
    options?: ReportOptions
): Promise<void>

export function getDeviceName(
    capabilities: Capabilities.TestrunnerCapabilities | Capabilities.ResolvedTestrunnerCapabilities
): string

Import

import { aggregateSelectorPerformanceData, getDeviceName } from './mobileSelectorPerformanceOptimizer/aggregator.js'

I/O Contract

Inputs

Name	Type	Required	Description
capabilities	Capabilities.ResolvedTestrunnerCapabilities	Yes	Capabilities used to extract device name as a fallback
maxLineLength	`number`	Yes	Maximum line length for CLI report line wrapping
writeFn	`(message: string) => void`	No	Custom write function for output; defaults to `process.stdout.write`
reportDirectory	`string`	No	Directory path where JSON and markdown reports are written
options	`ReportOptions`	No	Flags controlling enableCliReport and enableMarkdownReport output

Outputs

Name	Type	Description
aggregateSelectorPerformanceData return	`Promise<void>`	Resolves when all reports have been written; throws SevereServiceError if reportDirectory is missing
getDeviceName return	`string`	Device name extracted from capabilities, or 'unknown' if not found

Usage Examples

Aggregating Data in onComplete

import { aggregateSelectorPerformanceData } from './mobileSelectorPerformanceOptimizer/aggregator.js'

async onComplete(exitCode: number, config: Options.Testrunner, capabilities: Capabilities.TestrunnerCapabilities) {
    await aggregateSelectorPerformanceData(
        capabilities,
        100,                // maxLineLength
        undefined,          // default writeFn
        './reports',        // reportDirectory
        { enableCliReport: true, enableMarkdownReport: true }
    )
}

Extracting Device Name

import { getDeviceName } from './mobileSelectorPerformanceOptimizer/aggregator.js'

const deviceName = getDeviceName(capabilities)
// e.g., "iPhone 15 Pro" or "unknown"

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Principle

Implementation

Heuristic

Environment