https://github.com/mfellner/partialize

Typesafe proxies.
https://github.com/mfellner/partialize

typescript

Last synced: 3 months ago
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Typesafe proxies.

• Host: GitHub
• URL: https://github.com/mfellner/partialize
• Owner: mfellner
• License: mit
• Created: 2018-04-06T11:19:08.000Z (about 7 years ago)
• Default Branch: master
• Last Pushed: 2018-08-02T08:03:54.000Z (almost 7 years ago)
• Last Synced: 2025-03-24T02:36:38.318Z (3 months ago)
• Topics: typescript
• Language: TypeScript
• Size: 88.9 KB
• Stars: 0
• Watchers: 0
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# partialize

[![Travis](https://img.shields.io/travis/mfellner/partialize.svg)](https://travis-ci.org/mfellner/partialize)

[![Codecov](https://img.shields.io/codecov/c/github/mfellner/partialize.svg)](https://codecov.io/gh/mfellner/partialize)

[![codebeat](https://codebeat.co/badges/1c20b7a3-b782-4f84-ba00-d2ee99d198f8)](https://codebeat.co/projects/github-com-mfellner-partialize-master)

[![npm](https://img.shields.io/npm/v/@mfellner/partialize.svg)](https://www.npmjs.com/package/@mfellner/partialize)

[![license](https://img.shields.io/github/license/mfellner/partialize.svg)](https://choosealicense.com/licenses/mit)

Turn objects into typesafe proxies to access potentially undefined properties.

### Getting started

Let's say you download some unsafe data that should match a given interface:

```typescript

interface Something {

  foo?: {

    bar?: {

      str?: string;

    };

    baz?: {

      num?: number;

    };

  };

}

const data: Something = await fetch(url).then(r => r.json());

```

Some properties may be present but others may not!

```typescript

const str = data.foo!.bar!.str; // OK?

const num = data.foo!.baz!.num; // Error?

```

Use **partialize** to wrap an object in a typesafe [Proxy](https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Proxy):

```typescript

import partialize, { Part } from '@mfellner/partialize';

const some: Part = partialize(data);

```

Now all the declared properties of the object will definitely be defined! That's because each value is turned into an object with all the original properties of that value plus a special `$resolve()` function. In order to retrieve the original raw value you simply call `$resolve()`:

```typescript

const str: string | undefined = data.foo.bar.str.$resolve(); // without fallback

const str: string = data.foo.bar.str.$resolve('fallback'); //  with fallback

```

See [test/index.test.ts](test/index.test.ts) for some examples.