Validation

Every question can have validation options. All basic angular validators are included in the core package. There is also the possibility to register custom sync and async validators.

Included validation options

• required: boolean

• min: number

• minLength: number

• max: number

• maxLength: number

• email: boolean

• pattern: string or regular expression

Example

const question: Question = {
  id: 'example input',
  type: 'input',
  label: 'Row 2',
  validation: {
    minLength: 5,
    required: true,
    min: 10,
    minLength: 20,
    max: 30,
    maxLength: 34,
    email: true,
    pattern: 'testing' | /test+3/
  }
}

Custom validators

Implementation

The sections Sync Validator and Async Validator will show how to implement a validator. The following sections should be read before. It contains general info about custom validators.

Arguments

A validator can have arguments. The arguments are separated with a : from the validator id. If there are multiple arguments they can be split with ,.

See the following examples of possible ids:

• custom-vali:test - custom-vali would be the id and the validator will get an argument array of ['test'].

• my-validator - validator without arguments

• my-complicated-validator:test,value,two - validator with 3 arguments, the arguments will look like ['test', 'value', 'two']

Registration

To register the validator it is required to specify it either in the root module or a child module.

FastFormsModule.forRoot({
  validators: [
    AsyncRequiredValidator
  ]
})

// OR

FastFormsModule.forChild({
  validators: [
    AsyncRequiredValidator
  ]
})

Usage

The validator can then be used in a question definition. It is possible to specify a single custom validator or an array of validators.

const question: Question =
  {
    id: 'test-input',
    type: 'input',
    label: 'Custom async required',
    validation: {
      custom: ['custom-start-with:testing', 'another-validator'],
      customAsync: 'custom-async-required'
    }
  }