validation.md

Validation

This module provides tools to validate values using existing or custom validators.

Validate a value

This example validates the value 5 using a list of validators (positive and max). The second one will fail.

validator.validate(5, [positive(), max(4)])

validate returns a list of errors, empty if validation succeeded, with the validator id and a message for each error:

[
  {
    id: 'max',
    message: 'Value should be lower than or equal to 4 (value given: 5)'
  }
]

Validate a class instance

Class instances can also be validated using validateInstance and annotations on class properties.

class User {
    constructor(
        @Min(4) public id: number
    ) {}
}

const user = new User(5)
validator.validateInstance(user, User)

Validate method parameters

Validators can also be applied to method parameters by applying the @HandledParameters annotation on the method. This way the parameters value will be validated when passed to a method call, throwing an exception if invalid.

class TestService {
    // Checks nb is a number > 1
    @HandledParameters()
    foo(@Typed(Number) @Min(1) nb: number): number {
        return nb * 2
    }

    // Checks user is a valid one
    @HandledParameters()
    bar(@Valid(User) user: User): number {
        return user.id
    }
}

Validators

Here is the list of validators integrated into Beemo.

Global:

• typed(type: Function) / @Typed(type: Function)
• notNull() / @NotNull()

Numbers:

• min(lowerBound: number) / @Min(lowerBound: number)
• max(upperBound: number) / @Max(upperBound: number)
• between(lowerBound: number, upperBound: number) / @Between(lowerBound: number, upperBound: number)
• positive() / @Positive()
• positiveOrZero() / @PositiveOrZero()
• negative() / @Negative()
• negativeOrZero() / @NegativeOrZero()

Strings:

• pattern(pattern: RegExp|string) / @Pattern(pattern: RegExp|string)
• email() / @Email()
• url() / @Url()

Arrays:

• notEmpty() / @NotEmpty() (works also with strings)
• length(length: number) / @Length(length: number)
• minLength(length: number) / @MinLength(length: number)
• maxLength(length: number) / @MaxLength(length: number)
• lengthBetween(minLength: number, maxLength: number) / @LengthBetween(minLength: number, maxLength: number)

Dates:

• past(from?: Date) / @Past(from?: Date)
• future(from?: Date) / @Future(from?: Date)

Classes:

• valid(classFn: Function) / @Valid(classFn: Function)