validate.js validating array elements

Question

I have a java script object that contains two array properties:

I'm using the validate.js library.

For example:

var customer = {
   name: 'Ted',
   address: 'some address',
   friends: ['Michelle','Elon'],
   purchases: [{ qty:1, goods: 'eggs'}, { qty:2, goods: 'apples'}]
}

I want to validate the following:

That the array of friends contains only elements of type string.
That the array of purchases contains at least 1 purchase but max 5 purchases and that the qty is always numeric.

How can i do that with validate.js?

It will be released soon: github.com/ansman/validate.js/pull/184 — Bruno Quaresma
– Bruno Quaresma, Commented Apr 6, 2017 at 12:56

Cumulo Nimbus · Accepted Answer · 2018-08-16 16:18:46Z

17

You could make a custom validator, let's call it array:

import validate from 'validate.js/validate'
import isEmpty from 'lodash-es/isEmpty'

validate.validators.array = (arrayItems, itemConstraints) => {
  const arrayItemErrors = arrayItems.reduce((errors, item, index) => {
    const error = validate(item, itemConstraints)
    if (error) errors[index] = { error: error }
    return errors
  }, {})

  return isEmpty(arrayItemErrors) ? null : { errors: arrayItemErrors }
}

and then use it like:

const customerConstraints = {
  purchases: {
    array: {
      qty: {
        numericality: {
          onlyInteger: true,
          greaterThan: 0,
          lessThanOrEqualTo: 5
        }
      }
    }
  }
}

const customerErrors = validate(customer, customerConstraints)

then in the render block when iterating over the customer.purchases array you can see if any purchase items have an error by checking customerErrors.purchases.errors[index].error.qty

edited Aug 16, 2018 at 16:18

answered Jul 18, 2018 at 16:21

Cumulo Nimbus

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2 Comments

Aljohn Yamaro Over a year ago

Hi Good day, I am new to mongoose, I've been too many articles and forums regarding element(string) validation inside array but nothing works for me. I guess you may help me. As of now I have tags: [ {type: String, minLength: 2, maxLength:50, trim: true}] which is only min, maxLength is not working. Thank you

nvbalaji Over a year ago

I think the custom validator should check whether the input is an array or not. It should also check array elements are of type 'object' or not. In case of Objects it should use 'validate', and in case of primitive types it should use 'validate.single'

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