Workhar Playhar Monorepo

This monorepo contains three related libraries that work together to help you record, sanitize, extract, and replay HTTP API traffic in your tests:

Package	Description
mustachr	Extracts or injects values in string files using Mustache-style templates ({{ TOKEN }})
workhar	Converts .har files to .json fixtures and back
playhar	Ties everything together — record via CLI, then mock HARs during tests

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🎭 Playhar – Record, Template, and Replay HARs in Playwright

playhar is the core workflow layer that ties everything together.

It launches a real Playwright browser, records API traffic into a .har file, sanitizes sensitive values with mustache-style templates, and extracts response bodies into editable .json fixtures. These can then be rebuilt into usable HARs and replayed with page.routeFromHAR() in your tests.

Install

npm install --save-dev  playhar

Also ensure you have Playwright installed:

npm install -D @playwright/test

Example Config (playhar.config.ts)

import { defineConfig } from  'playhar';

export default defineConfig({
    directory: './recordings',
    baseRequestUrl: 'https://api.example.com',
    extractions: [
        {
            type: 'regex',
            property: 'SECRET_TOKEN',
            search: 'token":"[^"]*',
            replace: 'token":"{{ property }}"'
        }
    ],
});

CLI Usage

playhar record --url  http://localhost:5173 --config ./playhar.config.ts
playhar mock --name  auth-flow --injections ./injections.json --out ./mocked.har

Programmatic Usage

import { record, mock, configFromFile } from  'playhar';

const config = await  configFromFile({ file: './playhar.config.ts', fallbacks: [] });
await record({ config, name: 'auth-flow', url: 'http://localhost:5173' });
const har = await  mock({
    config,
    name: 'auth-flow',
    injections: { SECRET_TOKEN: 'mocked-token' },
});

---

Workhar – Convert HAR Files to JSON and Back

workhar is the engine that powers Playhar’s extraction and hydration process. It turns .har files into structured .json files you can edit, and then regenerates HARs from those responses.

Install

npm install --save-dev workhar

CLI Usage

workhar  har2json  ./recording.har  ./.workhar  --json  ./json
workhar  json2har  ./.workhar  ./hydrated.har  --json  ./json

Programmatic Usage

import { har2json, json2har } from  'workhar';

await har2json({
    fromHarFile: './recording.har',
    toWorkharFile: './.workhar',
    withJsonDirectory: './json',
});

await json2har({
    fromWorkHarFile: './.workhar',
    withJsonDirectory: './json',
    toHarFile: './hydrated.har',
});

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🥸 Mustachr – Template and Inject Mustache Files

mustachr lets you extract hardcoded secrets or values from text files and replace them with mustache-style template tokens (like {{ SECRET }}). You can later inject them back using an injection map.

Install

npm install --save-dev mustachr

CLI Usage

mustachr extract ./api.har --extractions ./mustachr.extractions.ts
mustachr inject ./api.har --injections ./mustachr.injections.ts

Programmatic Usage

import { extract, inject, defineExtractions, defineInjections } from  '@adameisfeld/mustachr';

const extracted = await  extract({
    input: fs.readFileSync('./api.har', 'utf-8'),
    extractions: defineExtractions([
        {
            type: 'string',
            property: 'SECRET',
            search: 'SuperSecret123',
            replace: '{{ property }}',
        },
    ]),
});

const hydrated = inject({
    input: extracted,
    injections: defineInjections({ SECRET: 'MockedValue' }),
});

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Testing

All packages are 100% test-covered and tested with Vitest. Run all tests from the monorepo root:

npm run test

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Repository Structure

workhar-playhar/
    ├── packages/
    │ ├── mustachr/
    │ ├── workhar/
    │ └── playhar/
    ├── README.md
    ├── turbo.json
    └── ...

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License

MIT © 2025 Adam Eisfeld