The length validator combines the minLength and maxLength validators to check that the length of a string value is within a range. Both the minLength and maxLength values are inclusive.

If the value being validated is null or an empty string, then the result will be valid. This respects the rule of thumb described in the notes for the required validator.

Named Props

  • minLength: The minimum value compared against

  • maxLength: The maximum value compared against


The length validator supports three parameter signatures:

  1. length(minLength, maxLength) where the minLength and maxLength named props are specified as values

  2. length(propsObject) where the props object contains minLength and maxLength named props

  3. length(propsFunction) where the props function returns a props object with minLength and maxLength named props


import validate, {length} from 'strickland';

// As value parameters
const maxLengthBetween5and10 = length(5, 10);

// As named props
const maxLengthBetween10and20 = length({
    minLength: 10,
    maxLength: 20,
    message: 'Must have a length between 10 and 20'

// As a function that resolves to have the named props
const lengthValidator = length((context) => ({
    minLength: context.minLength,
    maxLength: context.maxLength,
    message: `Must have a length between ${context.minLength} and ${context.maxLength}`

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