Developers

Mock data generator for form tests

One file. Zero dependencies. No network. Generate realistic test values, then fill a whole form with a single call — the same values the Chrome extension writes.

npm install mock-data-form-filler

MIT · ~9 KB · Node 14+ and every modern browser · no runtime deps

Try it here

This form is filled by MockFiller.fillAll(form) — the exact file the package ships.

Click “Fill the form” to see the values.

Use it in your tests

The package has no build step and no framework bindings. Load it as a script, or import it in the test runner.

Browser

<script src="/node_modules/mock-data-form-filler/index.js"></script>
<script>
  // fills every safe field under the given root
  MockFiller.fillAll(document); // → { filled: 7 }
</script>

Playwright

const { test, expect } = require("@playwright/test");

test("signup accepts mock data", async ({ page }) => {
  await page.goto("/signup");
  await page.addScriptTag({ path: require.resolve("mock-data-form-filler") });
  const { filled } = await page.evaluate(() => MockFiller.fillAll(document));
  expect(filled).toBeGreaterThan(4);
});

Cypress

// cypress/support/e2e.js
import MockFiller from "mock-data-form-filler";

// in a spec
cy.visit("/signup");
cy.document().then((doc) => MockFiller.fillAll(doc));

Deterministic runs

MockFiller.setSeed(42);
MockFiller.email(); // the same string on every run
MockFiller.reset(); // back to Math.random

API

Method	Returns
`firstName()` `lastName()` `fullName()`	`"Alex"`, `"Smith"`, `"Alex Smith"`
`email()` `phone()` `url()` `username()`	`alex.smith42@example.com`, `+15550123456`
`company()` `street()` `city()` `state()` `zip()` `country()`	a full address block
`date()` `time()` `month()` `week()` `datetime()`	values that native inputs accept
`number(min?, max?)` `color()` `sentence()` `password()`	`"42"`, `"#3f8ac1"`, a short sentence
`record()`	all values in one object — handy for API fixtures
`fill(el, options?)`	`true` when a value was written
`fillAll(root?, options?)`	`{ filled: number }`
`setSeed(n)` `reset()` `isSeeded()`	reproducible output

Detection reads type, autocomplete, name, id, placeholder, aria-label and the closest <label> — so it also works on forms without semantic markup.

Why this one

No network and no account: nothing leaves the machine, nothing is logged.
Same value sets as the extension, so manual QA and E2E see the same data.
Skips hidden, disabled, readonly and captcha-like fields; passwords stay empty unless you pass { password: true }.
One file, MIT, no runtime dependencies — easy to vendor or pin.

FAQ

Does it only work in Chrome?

No. The extension is Chrome-only, but the package is plain JavaScript and runs in any modern browser, Playwright, Cypress and Node.

Does it call an API?

Never. Every value is generated locally with Math.random() or, if you call setSeed(), with a small deterministic PRNG.

Can I use it for manual testing too?

Yes — that is what the Chrome extension is for: click the toolbar icon or press Alt+Shift+F on any page.

Links

Package: npm · product home · test forms · fake data extension · privacy