object-fill-missing-keys/README.md

Add missing keys into plain objects, according to a reference object

<h1 align="center">object-fill-missing-keys</h1>

<p align="center">Add missing keys into plain objects, according to a reference object</p>

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## Install

This package is [pure ESM](https://gist.github.com/sindresorhus/a39789f98801d908bbc7ff3ecc99d99c). If you're not ready yet, install an older version of this program, 8.1.0 (`npm i object-fill-missing-keys@8.1.0`).

```bash
npm i object-fill-missing-keys
```

## Quick Take

```js
import { strict as assert } from "assert";

import { fillMissing } from "object-fill-missing-keys";

// deleting key 'c', with value 'd'
assert.deepEqual(
  fillMissing(
    {
      // input object that could have came from JSON
      b: "b",
    },
    {
      // schema reference object
      a: false,
      b: false,
      c: false,
    },
  ),
  {
    // patched result
    a: false,
    b: "b",
    c: false,
  },
);
```

## Documentation

Please [visit codsen.com](https://codsen.com/os/object-fill-missing-keys/) for a full description of the API. If you’re looking for the **Changelog**, it’s [here](https://github.com/codsen/codsen/blob/main/packages/object-fill-missing-keys/CHANGELOG.md).

## Contributing

To report bugs or request features or assistance, [raise an issue](https://github.com/codsen/codsen/issues/new/choose) on GitHub.

## Licence

MIT License

Copyright © 2010-2025 Roy Revelt and other contributors

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