:rocket: TypeScript Decorator Validation :rocket:

:star: Class entity validations made easy with the help of
@Decorators

:star: Allows strict type checking when applying decorator validators

:star: Works perfectly with existing TypeScript-first applications

Table of Contents

- Installation
- Contribute
- Documentation
- Goals and TODOs
- Examples

Installation

1. Install library dependency
``
npm install typescript-decorator-validation
`
2. Allow experimental decorators configuration in your tsconfig.json.

This removes IDE errors which could pop-up
`ts
{
"compilerOptions": {
"experimentalDecorators": true,
"emitDecoratorMetadata": true,
/ ... /
}
}
`
3. Add babel configuration to your tsconfig.json.

This allows for type-safety checking
`ts
{
plugins: [
"babel-plugin-transform-typescript-metadata",
["@babel/plugin-proposal-decorators", { legacy: true }],
["@babel/plugin-proposal-class-properties", { loose: true }],
],
presets: ["@babel/preset-typescript"],
}
`

Contribute

1. Open bash terminal
2. Change directory to your desired position
3. Clone the repository main branch
`bash
git clone https://github.com/brunotot/typescript-decorator-validation.git
`
4. Checkout a new branch
`bash
git checkout -b "[issue-number]-[issue-description]"
`
5. Commit and push changes
6. Open pull request

Documentation

$3

| Method | Parameters | Returns | Description |
|---------------|------------|---------|-------------|
|constructor |clazz: Class\|ValidationHandler\|instantiates ValidationHandler class with the given decorated class to validate|
| validationData | | ValidationData\ | returns calculated validation data for given class through its metadata decorators |
| hasErrors | state: Object | boolean | returns true if state object has errors |
| getErrors | state: Object | ErrorData | returns object error state from the calculated validation metadata for the given state object |
| validate | state: Object | StateValidationResult | returns object state validation result from the calculated validation metadata for the given object state |
| buildInstance | state: Object | T | returns instantiated class T which is used to construct ValidationHandler |

Goals and TODOs

- [x] Implement strict type checking
- [x] Implement predefined decorator validators
- [ ] Write documentation
- [ ] Implement the logic so the library can be used easily in CI tests
- [ ] Implement tests for predefined decorator validators
- Write implementation libraries for popular front-end frameworks
- [x] React
- [ ] Angular
- [ ] Svelte
- [ ] Vue
- [ ] Solid



Examples

A basic TypeScript form can look something like
`typescript
import { validators } from 'react-decorate-form';

export type UserFormFields = {
confirmPassword: string;
firstName: string;
lastName: string;
password: string;
url: string;
age: number;
};

export default class UserForm implements UserFormFields {
@validators.string.Size({ min: 5 })
@validators.string.NotEmpty()
firstName!: string;

@validators.string.NotEmpty()
lastName!: string;

@validators.string.NotEmpty()
@validators.string.Password()
password!: string;

confirmPassword!: string;

@validators.string.URL()
url!: string;

@validators.number.Range({ min: 18, max: 100 })
age!: number;

@validators.boolean.AssertTrue('Passwords must match')
get passwordsMatch(): boolean {
return this.password === this.confirmPassword;
}
}
``
And with some styling we can display the form which can look something like:

!example form