Built-In Validator: every

Strickland provides an every validator. The every validator operates over an array and it will only return a valid result if all validators in the array are valid. The every validator will short-circuit (exit early) as soon as an invalid result is encountered. This allows chaining of validators where one validator's logic might depend on a previous validator already being valid.

Parameters

The first parameter to the every validator factory is the array of validators. Validator props can also be supplied either as an object or as a function that accepts context and returns a validator props object.

const atLeast5Chars = every(
    [
        required(),
        minLength(5)
    ],
    {message: 'Must have at least 5 characters'}
);

const result = validate(atLeast5Chars, '1234');

const requiredWithMinLength = every(
    [
        required(),
        minLength((context) => ({minLength: context.minLength}))
    ],
    (context) => ({message: `Must have at least ${context.minLength} characters`})
);

Result Properties

  • every: The array of validation results produced during validation

The every validator adds an every property to the validation result with the validation results of every validator that was validated in the array of validators. Validators that were not executed because of validation failing early will be omitted from this array. The validation result property is named every to match the name of the validator (this is a common pattern in Strickland).

import validate, {every, required, minLength, maxLength} from 'strickland';

const mustExistWithLength5to10 = every([
    required({message: 'Required'}),
    minLength({minLength: 5, message: 'Must have at least 5 characters'}),
    maxLength({maxLength: 10, message: 'Must have at most 10 characters'})
]);
const result = validate(mustExistWithLength5to10, '1234');

/*
    result = {
        isValid: false,
        value: '1234',
        required: true,
        minLength: 5,
        message: 'Must have at least 5 characters',
        every: [
            {
                isValid: true,
                value: '1234',
                required: true,
                message: 'Required'
            },
            {
                isValid: false,
                value: '1234',
                minLength: 5,
                message: 'Must have at least 5 characters'
            }
        ]
    }
 */

There are a few notable characteristics of this result:

  1. The properties from each executed validator are added to the top-level result
    • The required validator added the required: true property to the result
    • The minLength validator added the minLength: 5 property to the result
  2. Property collisions are resolved using last-in-wins
    • In this example, the message from the required validator was replaced with the message from the minLength validator
    • This allows the message to reflect the deepest validation result in the array
  3. Once validation fails for a validator, no further validation is performed
    • The maxLength validator was not executed
    • The props from the maxLength validator are not included on the result
    • The every array in the result does not include an item for the maxLength validator
  4. The top-level isValid prop on the result reflects the overall validation result

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