can-validate/docs/can-validate.md

Validation plugin for CanJS.

@module {Object} can-validate
@parent can-data-validation
@collection can-ecosystem
@group can-validate.methods 1 Methods
@group can-validate.types 2 Types
@package ../package.json

Shared utilities and type definitions to process validation errors.

@type {Object}

The `can-validate` module exports helpful methods used for validation and also describes
the different types used during validation.

```js
import validate from "my-validator";
import utils from "can-validate";

// Normalize errors into a flat structure
const errors = utils.formatErrors( validate( obj, constraints ), "flat" );
```

@body

## Usage

The [can-validate.formatErrors] method can be used to convert errors into something more useful.

```js
import { formatErrors } from "can-validate";
const errors = [
	"is required",
	{
		message: "must be a number",
		related: "age"
	}
];

formatErrors( errors, "object" );

//=> [{'*': ['is required']}, {'age': ['must be a number']}]

formatErrors( errors, "flat" );

//=> ['is required', 'must be a number']

formatErrors( errors, "errors" );

//=> [{message: 'is required', related: '*'}, {'age': ['must be a number']}]
```

## Types

Core definitions of types used in validation.

- [can-validate.error] A flexible typedef that describes a validation error.
- [can-validate.errors] Different error types understood by `can-validate`.
- [can-validate.validator] A function that validates a given value against registered constraints.