class-validator

# class-validator

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Allows use of decorator and non-decorator based validation.
Internally uses [validator.js][1] to perform validation.
Class-validator works on both browser and node.js platforms.

## Table of Contents

- [class-validator](#class-validator)
  - [Table of Contents](#table-of-contents)
  - [Installation](#installation)
  - [Usage](#usage)
    - [Passing options](#passing-options)
  - [Validation errors](#validation-errors)
  - [Validation messages](#validation-messages)
  - [Validating arrays](#validating-arrays)
  - [Validating sets](#validating-sets)
  - [Validating maps](#validating-maps)
  - [Validating nested objects](#validating-nested-objects)
  - [Validating promises](#validating-promises)
  - [Inheriting Validation decorators](#inheriting-validation-decorators)
  - [Conditional validation](#conditional-validation)
  - [Whitelisting](#whitelisting)
  - [Passing context to decorators](#passing-context-to-decorators)
  - [Skipping missing properties](#skipping-missing-properties)
  - [Validation groups](#validation-groups)
  - [Custom validation classes](#custom-validation-classes)
  - [Custom validation decorators](#custom-validation-decorators)
  - [Using service container](#using-service-container)
  - [Synchronous validation](#synchronous-validation)
  - [Manual validation](#manual-validation)
  - [Validation decorators](#validation-decorators)
  - [Defining validation schema without decorators](#defining-validation-schema-without-decorators)
  - [Validating plain objects](#validating-plain-objects)
  - [Samples](#samples)
  - [Extensions](#extensions)
  - [Release notes](#release-notes)
  - [Contributing](#contributing)

## Installation

```sh
npm install class-validator --save
```

> Note: Please use at least npm@6 when using class-validator. From npm@6 the dependency tree is flattened, which is required by `class-validator` to function properly.

## Usage

Create your class and put some validation decorators on the properties you want to validate:

```typescript
import {
  validate,
  validateOrReject,
  Contains,
  IsInt,
  Length,
  IsEmail,
  IsFQDN,
  IsDate,
  Min,
  Max,
} from 'class-validator';

export class Post {
  @Length(10, 20)
  title: string;

  @Contains('hello')
  text: string;

  @IsInt()
  @Min(0)
  @Max(10)
  rating: number;

  @IsEmail()
  email: string;

  @IsFQDN()
  site: string;

  @IsDate()
  createDate: Date;
}

let post = new Post();
post.title = 'Hello'; // should not pass
post.text = 'this is a great post about hell world'; // should not