Form.js

// resources/js/services/Form.js

import FormErrors from './FormErrors'

export default class {
    
    constructor (initialData = {}, submitCallback = null) {
        this._initialData = initialData
        this._submitCallback = submitCallback
        this.errors = new FormErrors()
        this.reset()
    }

    reset () {
        this.busy = false
        this.successful = false
        this.errors.clear()
        Object.assign(this, this._initialData)
    }

    async submit (...args) {
        if (this.busy || ! this._submitCallback) {
            return
        }
        this.beforeStart()
        const result = await this._submitCallback(this, ...args).catch(error => {
            this.onFailure(error)
            throw error
        })
        this.onSuccess()
        return result
    }

    export () {
        return { ...this }
    }

    beforeStart () {
        this.busy = true
        this.successful = false
        this.errors.clear()
    }

    onSuccess () {
        this.busy = false
        this.successful = true
    }

    onFailure (error) {
        this.busy = false
        if (error.response && error.response.data) {
            const { errors, message } = error.response.data
            this.setErrors(errors, message)
        }
    }

    setErrors (errors, message) {
        this.errors.set(errors, message)
    }
}

FormErrors.js

// resources/js/services/FormErrors.js

export default class {
    
    constructor () {
        this.errors = {}
        this.message = null
    }

    set (errors, message) {
        this.errors = errors || {};
        this.message = message || null;
    }

    has (field) {
        return Object.keys(this.errors).includes(field)
    }

    get (field) {
        if (this.has(field)) {
            const error = this.errors[field]
            return Array.isArray(error) && error.length > 0 ? error[0] : error
        }
    }

    clear (field) {
        if (field) {
            Vue.delete(this.errors, field);
        } else {
            this.errors = {}
            this.message = null
        }
    }
}