prisma-json-types-generator/README.md

Changes JsonValues to your custom typescript type

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<h1 align=center>
⚒️ Prisma Json Types Generator
</h1>

<h3 align=center>
A generator that changes the Prisma Client output to strongly type Json fields
</h3>

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```prisma
// schema.prisma

generator client {
  provider = "prisma-client-js"
}

/// Always after the prisma-client-js generator
generator json {
  provider = "prisma-json-types-generator"
  // namespace = "PrismaJson"
  // clientOutput = "<finds it automatically>"
  // (./ -> relative to schema, or an importable path to require() it)
}

model Example {
  /// [MyType]
  normal Json

  /// [MyType]
  optional Json?

  /// [MyType]
  array Json[]
}
```

```ts
// index.ts

import type { Example } from '@prisma/client';

declare global {
  namespace PrismaJson {
    // you can use classes, interfaces, types, etc.
    type MyType = boolean;
  }
}

function myFunction(example: Example) {
  // example.normal   is now a boolean
  // example.optional is now a boolean | null
  // example.array    is now a boolean[]
}
```

### How it works

> ⚠️ **It just changes the declaration files of your generated client, no runtime code is
> affected!**

By using the Typescript Compiler API, this generator parses the generated client's types
AST and looks for `Prisma.JsonValue` types [_(or related)_](src/helpers/regex.ts) and
replaces them with their corresponding type.

### Some types are still json!

There are some complex json types like `JsonFilter` and `JsonWithAggregatesFilter` that,
if typed, would impact the usability of the client. So, they are still json.

### `declare global` is not working!

Using `declare global` in a file that is not a module _(that is contains no
import/export)_ is an error since everything in such a file is in the global scope anyway.
You can either remove it or add an empty `export {}` to make it a module.

### Limitations

- This project **should be** a temporary workaround _(and possible solution)_ to
  https://github.com/prisma/prisma/issues/3219.

- Json types inside `type` declarations won't work. (see
  https://github.com/prisma/prisma/issues/13726)