Class AbstractValidator<T>Abstract

Readonlyvalue

addFailure

• addFailure(message: string, errorBuilder: ErrorBuilder): void

  Adds a validation failure and throws an error if the validator is configured to throw an error on failure.

  Parameters

  • message: string

    a message that explains what went wrong
  • errorBuilder: ErrorBuilder

    creates the error associated with this failure

  Returns void

addTypeError

• addTypeError(message: string): void

  Adds a TypeError validation failure and throws an error if the validator is configured to throw an error on failure.

  Parameters

  • message: string

    a message that explains what went wrong

  Returns void

and

• and(validation: (validator: this) => void): this

  Facilitates the validation of related properties. For example,

  ```ts requireThat(nameToFrequency, "nameToFrequency"). and(m => m.size().isPositive()). and(m => m.keySet().contains("John")); ```

  Any changes made during the validation process will impact this validator.

  Parameters

  • validation: (validator: this) => void

    the nested validation

  Returns this

  this

  Throws

  TypeError if validation is undefined or null

configuration

• configuration(): Configuration

  Returns Configuration

elseGetError

• elseGetError(): null | Error

  Returns null | Error

elseGetFailures

• elseGetFailures(): ValidationFailures

  Returns the array of failed validations.

  Returns ValidationFailures

  an array of failed validations

elseThrow

• elseThrow(): boolean

  Throws an error if a validation failed; otherwise, returns true.

  Returns boolean

  true if the validation passed

  Throws

  RangeError if a method precondition, class invariant, or method postcondition was violated

  Throws

  MultipleFailuresError if more than one validation failed. This error contains an array of the failures.

getContext

• getContext(): Map<string, unknown>

  Returns the contextual information for upcoming validations carried out by this validator. The contextual information is a map of key-value pairs that can provide more details about validation failures. For example, if the message is "Password may not be empty" and the map contains the key-value pair {"username": "john.smith"}, the error message would be:

  Password may not be empty
  username: john.smith
  Copy

  Returns Map<string, unknown>

  an unmodifiable map from each entry's name to its value

  See

  Validators.getContext

getContextAsString

• getContextAsString(): string

  Returns the contextual information associated with this validator.

  Returns string

  the contextual information associated with this validator

getName

• getName(): string

  Returns the name of the value.

  Returns string

  the name of the value

getNameOrValue

• getNameOrValue(
      namePrefix: string,
      name: null | string,
      valuePrefix: string,
      value: unknown,
  ): string

  Parameters

  • namePrefix: string

    the string to prepend to the name if the name is null
  • name: null | string

    the name of the value
  • valuePrefix: string

    the string to prepend to the value if the name is null
  • value: unknown

    a value

  Returns string

  the prefixed name if it is defined; otherwise, the prefixed string representation of the value

getScope

• getScope(): ApplicationScope

  Returns ApplicationScope

  the application configuration

getValue

• getValue(): T

  Returns the value that is being validated.

  Returns T

  the value

  Throws

  RangeError if the value is invalid (e.g. due to dereferencing a property of a null value)

getValueOrDefault

• getValueOrDefault(defaultValue: T): T

  Returns the value that is being validated.

  Parameters

  • defaultValue: T

    the fallback value to use if the value is invalid

  Returns T

  the validated value, or defaultValue if the value is invalid (e.g. due to dereferencing a property of a null value)
• getValueOrDefault(defaultValue: null | T): null | T

  Parameters

  • defaultValue: null | T

  Returns null | T

isEqualTo

• isEqualTo(expected: unknown): this

  Ensures that the value is equal to expected.

  Parameters

  • expected: unknown

    the expected value

  Returns this

  this

  Throws

  RangeError if the value is not equal to expected

  See

  An explanation of the output format

isInstanceOf

• isInstanceOf<U extends object>(
      expected: ClassConstructor<U>,
  ): UnknownValidator<U>

  Ensures that the value is an instance of a class.

  Type Parameters

  • U extends object

    the desired class

  Parameters

  • expected: ClassConstructor<U>

    the desired class

  Returns UnknownValidator<U>

  a validator for an object of the desired class

  Throws

  TypeError if the value or expected are undefined or null

  Throws

  RangeError if the value is not an instance of the desired class

isNotEqualTo

• isNotEqualTo(unwanted: unknown): this

  Ensures that the value is not equal to unwanted.

  Parameters

  • unwanted: unknown

    the unwanted value

  Returns this

  this

  Throws

  RangeError if the value is equal to expected

  See

  An explanation of the output format

isNotInstanceOf

• isNotInstanceOf<U extends object>(expected: ClassConstructor<U>): this

  Ensures that the value is not an instance of a class.

  Type Parameters

  • U extends object

  Parameters

  • expected: ClassConstructor<U>

  Returns this

  this

  Throws

  TypeError if the value or unwanted are undefined or null

  Throws

  RangeError if the value is an instance of the unwanted class

isNotNull

• isNotNull(): UnknownValidator<NonNullable<T>>

  Ensures that the value is not null.

  This method should be used to validate method arguments that are assigned to class fields but not accessed right away (such as constructor and setter arguments). It should also be used to validate any method arguments when the validator contains additional contextual information.

  Returns UnknownValidator<NonNullable<T>>

  this

  Throws

  TypeError if the value is null

isNotUndefined

• isNotUndefined(): UnknownValidator<Exclude<T, undefined>>

  Ensures that the value is not undefined.

  This method should be used to validate method arguments that are assigned to class fields but not accessed right away (such as constructor and setter arguments). It should also be used to validate any method arguments when the validator contains additional contextual information.

  Returns UnknownValidator<Exclude<T, undefined>>

  this

  Throws

  TypeError if the value is undefined

isNull

• isNull(): UnknownValidator<null>

  Ensures that the value is null.

  Returns UnknownValidator<null>

  this

  Throws

  TypeError if the value is not null

isType

• isType(expected: Type): this

  Ensures that the value has the specified type.

  Parameters

  • expected: Type

    the expected type of the value

  Returns this

  this

  Throws

  TypeError if the value is not an instance of the specified type

isUndefined

• isUndefined(): UnknownValidator<undefined>

  Ensures that the value is undefined.

  Returns UnknownValidator<undefined>

  this

  Throws

  TypeError if the value is not undefined

validationFailed

• validationFailed(): boolean

  Checks if any validation has failed.

  Returns boolean

  true if at least one validation has failed

withContext

• withContext(value: unknown, name: string): this

  Sets the contextual information for upcoming validations.

  This method adds contextual information to error messages. The contextual information is stored as key-value pairs in a map. Values set by this method override any values that are set using Validators.withContext.

  There is no way to remove contextual information from a validator. Thread-level contextual information is removed automatically.

  Parameters

  • value: unknown

    the value of the entry
  • name: string

    the name of an entry

  Returns this

  this

  Throws

  TypeError if name is undefined or null

  Throws

  RangeError if name:

  • contains whitespace
  • is empty
  • is already in use by the value being validated or the validator context