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+# 2.0 spec plan (Draft level)
+
+- custom element (e.g. `<v-validator></v-validator>`)
+    - custom element enable validation result scope that did **inherit** from user data scope. vue-validator do not operate user data via validation result scope
+    - `id` attribute: keep the validation result data in custom element (e.g. vm.$validators.validator1)
+    - `name` attribute: change the validator result scope namespace (e.g. default: `validity`)
+    - available multiple validator (e.g. vm.$validators.validator1, vm.$validators.validator2, ...)
+- set custom directive (`v-validate`) to target element
+    - specify **field name**: keep the validation result
+    - validation result format: object property base structure (e.g. `validity.field.constraint`)
+    - accessable validation result with property keypath base (e.g. `validity.username.xxx`)
+- support for each field, the following validation property
+    - `valid` (e.g. `validity.field.valid`)
+    - `invalid` (reverse of `valid`, e.g. `validity.field.invalid`)
+    - `touched` (input tag was focused, e.g. `validity.field.touched`)
+    - `untouched`
+    - `modified` (from **initial** field value, e.g. `validity.field.modified`)
+    - `dirty` (angluar-like, attached even **once**, e.g. `validity.field.dirty`)
+    - `pristine` (angluar-like, **not** attached even once, e.g. `validity.field.pristine`)
+    - `error` (error message from #51, e.g. `validity.field.error`)
+- support the following top level property that keep the validation result of all fields
+    - `valid` (when **all** property is valid, return `true`)
+    - `invalid` (if exist even **one** invalid property, return `true`)
+    - `touched` (if exist even **one** touched property, return `true`)
+    - `untouched`
+    - `modified` (if exist even **one** modified property, return `true`)
+    - `dirty` (if exist even **one** dirty property, return `true`)
+    - `pristine` (if exist even **one** pristine property, return `true`)
+    - `submitted`
+- build-in validators
+    - required
+    - pattern
+    - min
+    - max
+    - minLength
+    - maxLength
+- improve delay validator initialization feature
+    - custom element base (not for each custom directive)
+- validator use HTML5 Form attributes base. (e.g. `min`, `max` ...)
+    - support custom validator: use attribute (e.g. `myValidator1` -> `<input type="text" my-validator1="foo">`)
+    - support reactivity & function or inline expression like `v-on`: `{{ mustache }}` expressions (e.g. `<input type="text" min="{{constraints.min}}">`)
+    - support async validator
+- validator assets feature
+    - aseets management: like vue.js
+    - register/retrieve custom validator or build-in validtors
+
+## example
+
+```html
+<div id="app">
+    <h1>user registration</h1>
+    <v-validator id="validator1">
+        <form>
+            username:<input type="text" required maxLength="16" pattern="/[a-zA-Z0-9_-]/" exist v-validate="username"><br>
+            age:<input type="number" required min="{{constraints.age.min}}" max="{{constraintAgeMax}}" v-validate="age"><br>
+            email:<input type="email" required email v-validate="email"><br>
+            password:<input type="password" required minLength="8" v-validate="password"><br>
+            site:<input type="number" url v-validate="site"><br>
+            <button type="submit" value="join" v-class="disabled: invalid"><br>
+            <div>
+                <span v-if="validity.username.required">required username.</span>
+                <span v-if="validity.username.maxLength">too long username.</span>
+                <span v-if="validity.username.pattern">invalid username format.</span>
+                <span v-if="validity.username.exsit">already exist username.</span>
+                <span v-if="validity.age.required">required age.</span>
+                <span v-if="validity.age.min">too small age.</span>
+                <span v-if="validity.age.max">too big age.</span>
+                <span v-if="validity.email.required">required email.</span>
+                <span v-if="validity.email.email">invalid email format.</span>
+                <span v-if="validity.password.required">required password.</span>
+                <span v-if="validity.password.minLength">too short password.</span>
+                <span v-if="validity.site.url">invalid site url format.</span>
+            </div>
+        </form>
+    <v-validator>
+</div>
+```
+
+```javascript
+var Vue = require('vue')
+var VueValidator = require('vue-validator')
+
+//
+// register custom validators with validator assets
+//
+
+// url validator, sync validation
+VueValidator.asset('url', function (val) {
+    return /^(ftp|http|https):\/\/(\w+:{0,1}\w*@)?(\S+)(:[0-9]+)?(\/|\/([\w#!:.?+=&%@!\-\/]))?$/.test(val)
+})
+
+// exist validator, async validaiton
+Vuevalidator.asset('exist', function (val) {
+    return function (resolve, reject) {
+        // server-side validation with ajax (e.g. using `fetch` case)
+        fetch('/validators/exist', {
+            method: 'post',
+            headers: {
+                'content-type': 'application/json',
+                'x-token': 'xxxxxxxx'
+            },
+            body: JSON.stringify({ username: val })
+        }).then(function (res) {
+            if (res.status === 200) {
+                resolve(true)
+            } else if (res.status === 400) {
+                resolve(false)
+            }
+        }).catch(function (err) {
+            // something todo ...
+            reject(new Error('exist validator fail'))
+        })
+    }
+})
+
+// email validator, async validation
+VueValidator.asset('email', function (val) {
+    return function (resolve, reject) {
+        // something todo ...
+    }
+})
+
+// install vue-validator
+Vue.use(VueValidator)
+
+// create Vue instance
+new Vue({
+    data: {
+        constraints: {
+            age: {
+                min: 18,
+            }
+        },
+        name: '',
+        age: 18,
+        address: '',
+        password: ''
+    },
+    computed: {
+        constraintAgeMax: function () {
+            return this.constraints.age.min * 5
+        }
+    }
+}).$mount('#app')
+```
+
+
+
+
+## Basic
+- custom element (e.g. `<v-validator></v-validator>`)
+    - custom element enable validation result scope. this means validation results scope are isolated from user data scope.
+    - specify `id` attribute that keep the validation result data in custom element (e.g. vm.$validators.validator1)
+- set custom directive (`v-validate`) to target element
+    - specify **field name** that keep the validation result
+    - validation result format: object property base structure (e.g. `validity.field.constraint`)
+    - accessable validation result with property keypath base. (e.g. `validity.username.xxx`)
+- validation constraints use HTML5 Form attributes base. (e.g. `min`, `max` ...)
+    - validation constraint of custome validator: use attribute (e.g. `myValidator1` -> `<input type="text" my-validator1="foo">`)
+    - support reactivity: spcify `{{ mustache }}` expressions to attribute. (e.g. `<input type="text" min="{{constraints.min}}">`)
+- support each field the following property
+    - `valid` (e.g. `validity.field.valid`)
+    - `invalid` (e.g. `validity.field.invalid`)
+    - `modified` (e.g. `validity.field.modified`)
+    - `dirty` (angluar-like, e.g. `validity.field.dirty`)
+    - `pristine` (angluar-like, e.g. `validity.field.pristine`)
+- support the following top level property that keep the result of all fields
+    - `valid`
+    - `invalid`
+    - `modified`
+    - `dirty`
+    - `pristine`
+- set `constraints` to `option.validator` field.
+    - support async loading
+- spcify `constraints` to constraint attribute with `{{ mustache }}` expressions.
+
+
+Example:
+
+```html
+<div id="app">
+    <h1>user registration</h1>
+    <v-validator name="validator1">
+        <form>
+            username:<input type="text" required maxLength="16" pattern="/[a-zA-Z0-9_-]/" v-validate="username"><br>
+            age:<input type="number" required min="18" max="100" value="18" v-validate="age"><br>
+            email:<input type="text" required pattern="/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/" v-validate="email"><br>
+            password:<input type="password" required minLength="8" v-validate="password"><br>
+            <button type="submit" value="join" v-class="disabled: invalid"><br>
+            <div>
+                <span v-if="validity.username.required">required username.</span>
+                <span v-if="validity.username.maxLength">too long username.</span>
+                <span v-if="validity.username.pattern">invalid username format.</span>
+                <span v-if="validity.age.required">required age.</span>
+                <span v-if="validity.age.min">too small age.</span>
+                <span v-if="validity.age.max">too big age.</span>
+                <span v-if="validity.email.required">required email.</span>
+                <span v-if="validity.email.pattern">invalid email format.</span>
+                <span v-if="validity.password.required">required password.</span>
+                <span v-if="validity.password.minLength">too short password.</span>
+            </div>
+        </form>
+    <v-validator>
+</div>
+```
+
+```javascript
+var Vue = require('vue')
+var VueValidator = require('vue-validator')
+
+Vue.use(VueValidator)
+
+new Vue({
+    data: {
+        username: '',
+        age: 18,
+        email: '',
+        password: ''
+    }
+}).$mount('#app')
+```
+
+
+## Dynamic validation constraint (NEW)
+- set `constraints` to `option.validator` field.
+    - support async loading
+- spcify `constraints` to constraint attribute with `{{ mustache }}` expressions.
+
+
+```html
+<div id="app">
+    <h1>user registration</h1>
+    <v-validator name="validator2">
+        <form>
+            username:<input type="text" required maxLength="{{rules.username.maxLength}}" pattern="/[a-zA-Z0-9_-]/" v-validate="username"><br>
+            age:<input type="number" required min="{{rules.age.min}}" max="{{rules.age.max}}" value="{{age}}" v-validate="age"><br>
+            email:<input type="text" required pattern="{{rules.email.pattern}}" v-validate="email"><br>
+            password:<input type="password" required minLength="8" v-validate="password"><br>
+            <button type="submit" value="join" v-class="disabled: invalid"><br>
+            <!--
+            ...
+            -->
+        </form>
+    <v-validator>
+</div>
+```
+
+```javascript
+var Vue = require('vue')
+var VueValidator = require('vue-validator')
+
+Vue.use(VueValidator)
+
+new Vue({
+    data: {
+        username: '',
+        age: 18,
+        email: '',
+        password: ''
+    },
+    validators: {
+        validator2: {
+            // sync
+            constraints: {
+                username: {
+                    maxLength: 16
+                },
+                age: {
+                    min: 18,
+                    max: 100
+                },
+                email: {
+                    pattern: ''
+                }
+            },
+            // async
+            /*
+            constraints: function (resolve, reject) {
+                this.$http.get('/users/constraints', function (data, status, request) {
+                    resolve(data)
+                }).error(function (data, status, request) {
+                    reject(new Error('validation rule download error'))
+                })
+            }
+            */
+        }
+    },
+    ready: function () {
+        this.$validators.validator2.rules.age.max = 99
+    }
+}).$mount('#app')
+```
+
+
+## Lazy initialization (CAHNGE)
+
+```html
+<div id="app">
+    <h1>user setting</h1>
+    <v-validator name="validator1" wait-for={{onUserDataLoaded}}>
+        <form>
+            <!--
+            ...
+            -->
+        </form>
+    <v-validator>
+</div>
+```
+
+```javascript
+var Vue = require('vue')
+var VueValidator = require('vue-validator')
+
+Vue.use(VueValidator)
+
+new Vue({
+    data: function () {
+        // TODO: 
+        // if changed asynchronously resolved data loading in 1.0-beta, should be changed !!
+        return function (resolve, reject) {
+            var resource = this.$resource('/users/:id')
+            resource.get({ id: 1 }, function (data, status, request) {
+                resolve(data)
+            }).error(function (data, status, request) {
+                reject(new Error('fetch failed'))
+            })
+        }
+    }
+}).$mount('#app')
+```
+
+
+## Multiple validation (NEW)
+- You can create multiple validation with `v-validator` custom element.
+
+```html
+<div id="app">
+    <!-- validation 1 -->
+    <v-validator name="validator1">
+        <form>
+            username:<input type="text" required maxLength="16" pattern="/[a-zA-Z0-9_-]/" v-validate="username"><br>
+            <!-- 
+            ...
+            -->
+        </form>
+    <v-validator>
+
+    <!-- validation 2 -->
+    <v-validator name="validator2">
+        <form>
+            age:<input type="number" required min="18" max="100" value="18" v-validate="age"><br>
+            <!-- 
+            ...
+            -->
+        </form>
+    </v-validator>
+
+    <!-- validation 3 -->
+    <v-validator name="validator3">
+        <form>
+            email:<input type="text" required pattern="/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/" v-validate="email"><br>
+            <!-- 
+            ...
+            -->
+        </form>
+    </v-validator>
+
+    <!-- ... validation x -->
+
+    <button type="submit" value="join" v-class="disabled: isInvalid"><br>
+</div>
+```
+
+```javascript
+var Vue = require('vue')
+var VueValidator = require('vue-validator')
+
+Vue.use(VueValidator)
+
+var vm = new Vue({
+    data: {
+        username: '',
+        age: 18,
+        email: ''
+    },
+    validators: {
+        validator1: { // for validator1
+            // ...
+        },
+        validator2: { // for validator2
+            // ...
+        },
+        validator3: { // for validator3
+            // ...
+        },
+        // ...
+    },
+    computed: {
+        isInvalid: function () { // check invalid of all validators
+            return this.$validators.validator1.invalid ||
+                this.$validators.validator2.invalid ||
+                this.$validators.validator3.invalid
+        }
+    }
+}).$mount('#app')
+```
+
+
+## Build-in validator
+- required
+- pattern
+- min
+- max
+- minLength
+- maxLength
+- numeric (NEW)
+- integer (NEW)
+- float (NEW)
+- alpha (NEW)
+
+
+## User custom validator & Validator assets
+- You can defined custome validator
+- You can register/retrieve custom validator or build-in validtors at validator asset
+
+```html
+<div id="app">
+    <v-validator name="validator3">
+        <form>
+            name: <input type="text" required v-validate="name"><br>
+            address: <input type="text" v-validate="address: email"><br>
+            <input type="submit" value="send" v-if="valid && dirty">
+            <div>
+                <span v-if="validity.name.required">required your name.</span>
+                <span v-if="validity.address.email">invalid your email address format.</span>
+            </div>
+        </form>
+    </v-validator>
+</div>
+```
+
+```javascript
+var Vue = require('vue')
+var VueValidator = require('vue-validator')
+
+// register custom validators with validator assets
+VueValidator.validator('email', function (val) { // sync validator
+    return /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/.test(val)
+})
+VueValidator.validator('email-async', function (val) { // async validator
+    // validate at server-side
+    return function (resolve, reject) {
+        fetch('/validators/email', {
+            method: 'post',
+            headers: { 'content-type': 'application/json' },
+            body: JSON.stringify({ email: val })
+        }).then(function (res) {
+            if (res.status === 200) {
+                resolve(true)
+            } else if (res.status === 400) {
+                resolve(false)
+            }
+        }).catch(function (err) {
+            reject(new Error('email validator fail'))
+        })
+    }
+})
+
+Vue.use(VueValidator)
+
+new Vue({
+    data: {
+        name: '',
+        address: ''
+    }
+}).$mount('#app')
+```