Server-side input validation with Quasar (Vue) - vue.js

Question

I'm looking for a reusable solution for server side input validation with Quasar Framework.
I use the q-input field. There are 2 props that can be used for the error output error and error-message. My server response on a validation error is a 400 response with this json
{
errors: { username: ['Username is to long.', 'User not valid'] },
title: 'One or more validation errors occurred.',
status: 400,
traceId: '80000005-0000-ff00-b63f-84710c7967bb'
}
I am currently using this logic, but I cannot move it to a mixin because I need access to the error field. The full example is available here codesandbox.io
<q-input
v-model="username"
filled
label="Username *"
:error-message="getErrorForField('username')"
:error="isErrorForField('username')"
/>
getErrorForField(field) {
if (!this.errors) {
return ''
}
const keys = Object.keys(this.errors)
const key = keys.find(
element => element.toLowerCase() === field.toLowerCase()
)
if (this.errors[key]) {
return this.errors[key].join('\r\n')
}
},
isErrorForField(field) {
if (!this.errors) {
return false
}
const keys = Object.keys(this.errors)
const key = keys.find(
element => element.toLowerCase() === field.toLowerCase()
)
if (this.errors[key]) {
return true
}
}

Answer 1

I have found a solution with the new vue3 composition-api. I now have a reusable logic.
MyComponent.vue
<template>
<q-input
v-model="username"
filled
label="Username *"
:error-message="getErrorForField('username')"
:error="isErrorForField('username')"
/>
</template>
<script>
import { validationHelper } from 'src/helper/validationHelper'
export default {
name: 'MyComponent',
setup () {
const { showValidationError, setValidationErrors, getValidationErrors, hasValidationErrors } = validationHelper()
return {
showValidationError,
setValidationErrors,
getValidationErrors,
hasValidationErrors
}
},
methods: {
async add () {
try {
//axios request
} catch (error) {
this.setValidationErrors(error.response.data.errors)
this.showValidationError()
}
}
}
}
</script>
validationHelper.js
import { ref } from '#vue/composition-api'
export function validationHelper () {
const errors = ref([])
function getValidationErrorMessages (field) {
if (!errors.value) {
return []
}
const keys = Object.keys(errors.value)
const key = keys.find(element => element.toLowerCase() === field.toLowerCase())
if (errors.value[key]) {
return errors.value[key]
}
return []
}
function getValidationErrors (field) {
const errors = getValidationErrorMessages(field)
if (errors.length !== 0) {
return errors.join('\r\n')
}
return ''
}
function hasValidationErrors (field) {
if (getValidationErrorMessages(field).length !== 0) {
return true
}
return false
}
function setValidationErrors (payload) {
errors.value = payload
}
function showValidationError () {
this.$q.notify({
type: 'negative',
message: 'Validation failure',
caption: 'please check the inputs'
})
}
return {
showValidationError,
setValidationErrors,
getValidationErrors,
hasValidationErrors
}
}