Develop Reference

Next page does not open. Problem with pagination

I need to make a pagination in my task, but it is not working.
I made two buttons to which I attached the "click" event and I registered a property in the "data". When I click on the buttons, the property changes and is written to the link and in the same way changes the current 10 posts to the following.
But for some reason it does not work as it should work. Can someone please explain what my mistake is and if you can suggest some articles on the subject of "pagination".
This is my html:
<button type="button" #click="counter -=1" class="prev">Prev</button>
<div class="counter">{{ counter }}</div>
<button type="button" #click="counter +=1" class="next">Next</button>
This is my Vue:
export default {
name: 'app',
data () {
return {
counter: 1,
zero: 0,
posts: [],
createTitle: '',
createBody: '',
visiblePostID: ''
};
},
created () {
axios.get('http://jsonplaceholder.typicode.com/posts?_start=${this.counter}+${this.zero}&_limit=10').then(response => {
this.posts = response.data;
});
}
};

The created method is called only when the component is created. To make the GET request everytime the counter increase or decrease use watches link.
Your example will become:
export default {
name: 'app',
data () {
return {
counter: 1,
zero: 0,
posts: [],
createTitle: '',
createBody: '',
visiblePostID: '',
}
},
watch: {
counter: function(newValue, oldValue) {
this.getData()
}
}
created(){
this.getData()
},
methods: {
getData() {
axios.get(`http://jsonplaceholder.typicode.com/posts?_start=${this.counter}+${this.zero}&_limit=10`).then(response => {
this.posts = response.data
})
}
}
}

You need to create a watcher for your counter that fires a load method. This way every time your counter changes you'll load in the correct posts for the page in your paginated results.
export default {
name: 'app',
data () {
return{
counter: 1,
...
}
},
created(){
this.loadPosts()
},
watch: {
counter(newVal, oldVal){
this.loadPosts()
}
},
methods: {
loadPosts(){
axios.get('http://jsonplaceholder.typicode.com/posts?_start=${this.counter}+${this.zero}&_limit=10')
.then(response => {
this.posts = response.data
})
}
}
}

Maybe this can help you. https://scotch.io/courses/getting-started-with-vue/vue-events-build-a-counter
I don't know vue, but looks like you need a function to load new data

VueJS / JS DOM Watch / Observer in a multi phase render scenario

Scenario:
I’m developing a Vue scroll component that wraps around a dynamic number of HTML sections and then dynamically builds out vertical page navigation allowing the user to scroll or jump to page locations onScroll.
Detail:
a. In my example my scroll component wraps 3 sections. All section id’s start with "js-page-section-{{index}}"
b. The objective is to get the list of section nodes (above) and then dynamically build out vertical page (nav) navigation based on the n number of nodes found in the query matching selector criteria. Therefore, three sections will result in three page section navigation items. All side navigation start with “js-side-nav-{{index}}>".
c. Once the side navigation is rendered I need to query all the navigation nodes in order to control classes, heights, display, opacity, etc. i.e document.querySelectorAll('*[id^="js-side-nav"]');
EDIT
Based on some research here are the options for my problem. Again my problem being 3 phase DOM state management i.e. STEP 1. Read all nodes equal to x, then STEP 2. Build Side Nav scroll based on n number of nodes in document, and then STEP 3. Read all nav nodes to sync with scroll of document nodes:
Create some sort of event system is $emit() && $on. In my opinion this gets messy very quickly and feels like a poor solution. I found myself quickly jumping to $root
Vuex. but that feels like an overkill
sync. Works but really that is for parent child property state management but that again requires $emit() && $on.
Promise. based service class. This seems like the right solution, but frankly it became a bit of pain managing multiple promises.
I attempted to use Vue $ref but frankly it seems better for managing state rather than multi stage DOM manipulation where a observer event approach is better.
The solution that seems to work is Vues $nextTick(). which seems to be similar to AngularJS $digest. In essence it is a . setTimeout(). type approach just pausing for next digest cycle. That said there is the scenario where the tick doesn’t sync the time requires so I built a throttle method. Below is the code update for what is worth.
The refactored watch with nextTick()
watch: {
'page.sections': {
handler(nodeList, oldNodeList){
if (this.isNodeList(nodeList) && _.size(nodeList) && this.sideNavActive) {
return this.$nextTick(this.sideNavInit);
}
},
deep: true
},
},
The REFACTORED Vue component
<template>
<div v-scroll="handleScroll">
<nav class="nav__wrapper" id="navbar-example">
<ul class="nav">
<li role="presentation"
:id="sideNavPrefix + '-' + (index + 1)"
v-for="(item, key,index) in page.sections">
<a :href="'#' + getAttribute(item,'id')">
<p class="nav__counter" v-text="('0' + (index + 1))"></p>
<h3 class="nav__title" v-text="getAttribute(item,'data-title')"></h3>
<p class="nav__body" v-text="getAttribute(item,'data-body')"></p>
</a>
</li>
</ul>
</nav>
<slot></slot>
</div>
</template>
<script>
import ScrollPageService from '../services/ScrollPageService.js';
const _S = "section", _N = "sidenavs";
export default {
name: "ScrollSection",
props: {
nodeId: {
type: String,
required: true
},
sideNavActive: {
type: Boolean,
default: true,
required: false
},
sideNavPrefix: {
type: String,
default: "js-side-nav",
required: false
},
sideNavClass: {
type: String,
default: "active",
required: false
},
sectionClass: {
type: String,
default: "inview",
required: false
}
},
directives: {
scroll: {
inserted: function (el, binding, vnode) {
let f = function(evt) {
if (binding.value(evt, el)) {
window.removeEventListener('scroll', f);
}
};
window.addEventListener('scroll', f);
}
},
},
data: function () {
return {
scrollService: {},
page: {
sections: {},
sidenavs: {}
}
}
},
methods: {
getAttribute: function(element, key) {
return element.getAttribute(key);
},
updateViewPort: function() {
if (this.scrollService.isInCurrent(window.scrollY)) return;
[this.page.sections, this.page.sidenavs] = this.scrollService.updateNodeList(window.scrollY);
},
handleScroll: function(evt, el) {
if ( !(this.isScrollInstance()) ) {
return this.$nextTick(this.inViewportInit);
}
this.updateViewPort();
},
getNodeList: function(key) {
this.page[key] = this.scrollService.getNodeList(key);
},
isScrollInstance: function() {
return this.scrollService instanceof ScrollPageService;
},
sideNavInit: function() {
if (this.isScrollInstance() && this.scrollService.navInit(this.sideNavPrefix, this.sideNavClass)) this.getNodeList(_N);
},
inViewportInit: function() {
if (!(this.isScrollInstance()) && ((this.scrollService = new ScrollPageService(this.nodeId, this.sectionClass)) instanceof ScrollPageService)) this.getNodeList(_S);
},
isNodeList: function(nodes) {
return NodeList.prototype.isPrototypeOf(nodes);
},
},
watch: {
'page.sections': {
handler(nodeList, oldNodeList){
if (this.isNodeList(nodeList) && _.size(nodeList) && this.sideNavActive) {
return this.$nextTick(this.sideNavInit);
}
},
deep: true
},
},
mounted() {
return this.$nextTick(this.inViewportInit);
},
}
</script>
END EDIT
ORIGINAL POST
Problem & Question:
PROBLEM:
The query of sections and render of navs work fine. However, querying the nav elements fails as the DOM has not completed the render. Therefore, I’m forced to use a setTimeout() function. Even if I use a watch I’m still forced to use timeout.
QUESTION:
Is there a promise or observer in Vue or JS I can use to check to see when the DOM has finished rendering the nav elements so that I can then read them? Example in AngularJS we might use $observe
HTML EXAMPLE
<html>
<head></head>
<body>
<scroll-section>
<div id="js-page-section-1"
data-title="One"
data-body="One Body">
</div>
<div id="js-page-section-2"
data-title="Two"
data-body="Two Body">
</div>
<div id="js-page-section-3"
data-title="Three"
data-body="THree Body">
</div>
</scroll-section>
</body>
</html>
Vue Compenent
<template>
<div v-scroll="handleScroll">
<nav class="nav__wrapper" id="navbar-example">
<ul class="nav">
<li role="presentation"
:id="[idOfSideNav(key)]"
v-for="(item, key,index) in page.sections.items">
<a :href="getId(item)">
<p class="nav__counter">{{key}}</p>
<h3 class="nav__title" v-text="item.getAttribute('data-title')"></h3>
<p class="nav__body" v-text="item.getAttribute('data-body')"></p>
</a>
</li>
</ul>
</nav>
<slot></slot>
</div>
</template>
<script>
export default {
name: "ScrollSection",
directives: {
scroll: {
inserted: function (el, binding, vnode) {
let f = function(evt) {
_.forEach(vnode.context.page.sections.items, function (elem,k) {
if (window.scrollY >= elem.offsetTop && window.scrollY <= (elem.offsetTop + elem.offsetHeight)) {
if (!vnode.context.page.sections.items[k].classList.contains("in-viewport") ) {
vnode.context.page.sections.items[k].classList.add("in-viewport");
}
if (!vnode.context.page.sidenavs.items[k].classList.contains("active") ) {
vnode.context.page.sidenavs.items[k].classList.add("active");
}
} else {
if (elem.classList.contains("in-viewport") ) {
elem.classList.remove("in-viewport");
}
vnode.context.page.sidenavs.items[k].classList.remove("active");
}
});
if (binding.value(evt, el)) {
window.removeEventListener('scroll', f);
}
};
window.addEventListener('scroll', f);
},
},
},
data: function () {
return {
page: {
sections: {},
sidenavs: {}
}
}
},
methods: {
handleScroll: function(evt, el) {
// Remove for brevity
},
idOfSideNav: function(key) {
return "js-side-nav-" + (key+1);
},
classOfSideNav: function(key) {
if (key==="0") {return "active"}
},
elementsOfSideNav:function() {
this.page.sidenavs = document.querySelectorAll('*[id^="js-side-nav"]');
},
elementsOfSections:function() {
this.page.sections = document.querySelectorAll('*[id^="page-section"]');
},
},
watch: {
'page.sections': function (val) {
if (_.has(val,'items') && _.size(val.items)) {
var self = this;
setTimeout(function(){
self.elementsOfSideNavs();
}, 300);
}
}
},
mounted() {
this.elementsOfSections();
},
}
</script>

I hope I can help you with what I'm going to post here. A friend of mine developed a function that we use in several places, and reading your question reminded me of it.
"Is there a promise or observer in Vue or JS I can use to check to see when the DOM has finished rendering the nav elements so that I can then read them?"
I thought about this function (source), here below. It takes a function (observe) and tries to satisfy it a number of times.
I believe you can use it at some point in component creation or page initialization; I admit that I didn't understand your scenario very well. However, some points of your question immediately made me think about this functionality. "...wait for something to happen and then make something else happen."
<> Credits to #Markkop the creator of that snippet/func =)
/**
* Waits for object existence using a function to retrieve its value.
*
* #param { function() : T } getValueFunction
* #param { number } [maxTries=10] - Number of tries before the error catch.
* #param { number } [timeInterval=200] - Time interval between the requests in milis.
* #returns { Promise.<T> } Promise of the checked value.
*/
export function waitForExistence(getValueFunction, maxTries = 10, timeInterval = 200) {
return new Promise((resolve, reject) => {
let tries = 0
const interval = setInterval(() => {
tries += 1
const value = getValueFunction()
if (value) {
clearInterval(interval)
return resolve(value)
}
if (tries >= maxTries) {
clearInterval(interval)
return reject(new Error(`Could not find any value using ${tries} tentatives`))
}
}, timeInterval)
})
}
Example
function getPotatoElement () {
return window.document.querySelector('#potato-scroller')
}
function hasPotatoElement () {
return Boolean(getPotatoElement())
}
// when something load
window.document.addEventListener('load', async () => {
// we try sometimes to check if our element exists
const has = await waitForExistence(hasPotatoElement)
if (has) {
// and if it exists, we do this
doThingThatNeedPotato()
}
// or you could use a promise chain
waitForExistence(hasPotatoElement)
.then(returnFromWaitedFunction => { /* hasPotatoElement */
if (has) {
doThingThatNeedPotato(getPotatoElement())
}
})
})

Values not reactive once available in Vuex Store

So I'm retrieving my data from my api using vue-resource which is happening correctly, the state is updated and from the console I am able to see the values I'm requesting. My problem is that when the application loads the data from the store doesn't seem to be impacting the application on load, but if for example I change between pages the information is displayed correctly. This is leading me to believe somewhere along the way I have gotten the life cycle hooks incorrect, or I have handled the state incorrectly inside vuex.
Vuex store
import Vue from 'vue'
import Vuex from 'vuex'
import VueResource from 'vue-resource'
Vue.use(VueResource)
Vue.use(Vuex)
const state = {
twitter: 0,
instagram: 0,
youtube: 0,
twitch: 0
}
const actions = {
LOAD_METRICS: ({commit}) => {
Vue.http.get('http://109.74.195.166:2000/metrics').then(response => {
let out = [{
twitter: Number(response.body[0].twitter),
instagram: Number(response.body[0].instagram),
youtube: Number(response.body[0].youtube),
twitch: Number(response.body[0].twitch)
}]
commit('SET_METRICS', out)
}).catch((e) => {
console.log(e)
})
}
}
const mutations = {
SET_METRICS (state, obj) {
state.twitter = obj[0].twitter
state.instagram = obj[0].instagram
state.youtube = obj[0].youtube
state.twitch = obj[0].twitch
}
}
const getters = {}
export default new Vuex.Store({
state,
getters,
actions,
mutations
})
Here I am trying to dispatch an event to gather the needed information using a mutation.
<template>
<div id="app">
<NavigationTop></NavigationTop>
<router-view></router-view>
<SocialBar></SocialBar>
<CopyrightBar></CopyrightBar>
</div>
</template>
<script>
export default {
name: 'app',
ready: function () {
this.$store.dispatch('LOAD_METRICS')
}
}
</script>
<style>
#import url('https://fonts.googleapis.com/css?family=Roboto:400,700,900');
#app {
font-family: 'Roboto', sans-serif;
-webkit-font-smoothing: antialiased;
-moz-osx-font-smoothing: grayscale;
text-align: center;
color: white;
background: url('./assets/Images/bodyBackground.jpg');
}
</style>
Then finally I am requesting the information inside of the component to be used by countup.js and also giving it to the method inside data.
<template>
<div class="hero">
<div class="container hero-content">
<div class="row hero-back align-items-end">
<div class="col-lg-6">
<div class="row">
<div class="col-lg-6" v-for="icons in socialIcons">
<Hero-Tile
:name="icons.name"
:icon="icons.iconName"
:count="icons.count"
:numeric="icons.numeric"
></Hero-Tile>
<h1>{{origin}}</h1>
</div>
</div>
</div>
</div>
</div>
<div class="diagonal-left-lines"></div>
<div class="home-hero-img"><img class="img-fluid" src="../../assets/Images/home-hero.jpg"></div>
</div>
</template>
<script>
import HeroTile from './Hero-Tile'
import CountUp from 'countup.js'
export default {
components: {HeroTile},
name: 'hero',
data () {
return {
origin: '',
socialIcons: [
{
name: 'twitter',
iconName: 'twitter',
count: this.$store.state.twitter,
numeric: 26000
},
{
name: 'instagram',
iconName: 'instagram',
count: this.$store.state.instagram,
numeric: 35000
},
{
name: 'youtube',
iconName: 'youtube-play',
count: this.$store.state.youtube,
numeric: 15000
},
{
name: 'twitch',
iconName: 'twitch',
count: this.$store.state.twitch,
numeric: 127000
}
]
}
},
methods: {
updateNumbers: function () {
let options = {
useEasing: true,
useGrouping: true,
separator: ',',
decimal: '.',
prefix: '',
suffix: 'K'
}
function kFormatter (num) {
return num > 999 ? (num / 1000).toFixed(1) : num
}
let twitter = new CountUp('twitter', 0, kFormatter(this.$store.state.twitter), 0, 3, options)
let instagram = new CountUp('instagram', 0, kFormatter(this.$store.state.instagram), 0, 3, options)
let youtube = new CountUp('youtube', 0, kFormatter(this.$store.state.youtube), 0, 3, options)
let twitch = new CountUp('twitch', 0, kFormatter(this.$store.state.twitch), 0, 3, options)
twitter.start()
instagram.start()
youtube.start()
twitch.start()
}
},
mounted: function () {
this.updateNumbers()
}
}
</script>
To be clear at the moment it seems to just load '0k' so it's as if there is some form of race condition occurring causing it not to actually load the information on load-up. Though I'm not sure what the correct approach is here.

This was eventually solved by what I'm going to describe as hacking as I don't actually know the exact correct answer at this time. Though what I have does work.
Points of Interest below:
Store
LOAD_METRICS: ({commit}, context) => {
console.log(context)
if (context === true) {
return new Promise((resolve) => {
resolve('loaded')
})
}
return new Promise((resolve) => {
Vue.http.get('real ip is normally here').then(response => {
let out = {
twitter: Number(response.body[0].twitter),
instagram: Number(response.body[0].instagram),
youtube: Number(response.body[0].youtube),
twitch: Number(response.body[0].twitch),
loaded: false
}
commit('SET_METRICS', out)
resolve(out)
}).catch((e) => {
console.log(e)
})
})
}
In the above I am now sending an instance of the current store.state.metrics.loaded when the dispatch event is sent. Which is then checked to see the truthness of the current value, Because the first load should always return false we then return a promise utilizing an API call while also mutating the store so we have the values from later. Thus onwards because we mutated the loaded event to be true the next further instances shall return a value of true and a new promise will be resolved so we can make sure the .then() handler is present.
Component
created: function () {
this.$store.dispatch('LOAD_METRICS', this.$store.state.metrics.loaded).then((res) => {
if (res !== 'loaded') {
this.updateNumbers(res)
} else {
this.socialIcons[0].count = this.kFormatter(this.$store.state.metrics.twitter) + 'K'
this.socialIcons[1].count = this.kFormatter(this.$store.state.metrics.instagram) + 'K'
this.socialIcons[2].count = this.kFormatter(this.$store.state.metrics.youtube) + 'K'
this.socialIcons[3].count = this.kFormatter(this.$store.state.metrics.twitch) + 'K'
}
})
}
Within our component created life cycle hook we then use the resulting values to identify the path to be taken when the components are created within the DOM again, this time just loading the values and allow normal data binding to update the DOM.
I believe there is a better method of approach then deliberating the logic of the state within the action setter and returning a promise that is essentially redundant other than for ensuring the .then() handle is present.

Associate Lists and Tasks in Meteor todo

I'm building the todo application from the Meteor tutorial and continue it. I'm building some lists based on the task model, but I don't know how to join them and say when I click on one list, I want all the tasks from this one.
For the moment, I have the Tasks.js with:
'tasks.insert'(text, privacy, priority, listId) {
...
Tasks.insert({
text,
listId: listId,
owner: this.userId,
username: Meteor.users.findOne(this.userId).username,
});
},
Body.js
Template.body.events({
'submit .new-task' (event) {
event.preventDefault();
const listId = ???
const target = event.target;
const text = target.text.value;
...
Meteor.call('tasks.insert', text, privacy, priority, listId);
...
},
And then where I display it:
Template.body.helpers({
tasks() {
const instance = Template.instance();
if (instance.state.get('hideCompleted')) {
return Tasks.find({ checked: { $ne: true } }, { sort: Session.get("sort_order") });
}
return Tasks.find({}, { sort: Session.get("sort_order")});
},
lists() {
return Lists.find({}, { sort: { createdAt: -1 } });
},
I my body.html, I just display each items (lists and tasks) separately. But the problem is I don't know how to make the relation between both ...
Can you help me please ?
Thanks a lot

I see you are already using Session. Basically, you will use a Session variable that tracks what the list the user has selected, and then filter your tasks with that variable.
In your body, where you're displaying your list names, add the list's id as an HTML attribute:
{{#each lists}}
<a href='#' class='list-name' data-id='{{this._id}}'>
{{this.name}}
</a>
{{/each}}
Add an event for clicking on a list name that saves its id to a Session variable:
Template.body.events({
'click .list-name' (event) {
event.preventDefault();
Session.set('listId', event.currentTarget.attr('data-id'))
}
})
In your tasks helper, filter your query using the Session variable:
return Tasks.find(
{ listId: Session.get('listId') },
{ sort: Session.get("sort_order") }
);
Let me know if anything could be more clear.

Subscribing the collection (Meteor)

I have some specific problem.
I use MeteorJS and installed yogiben:admin. I tried to build some schema, but I have an error after updating something.
I want to add that I have subpages in page, maybe that's the problem?
That's what I get after adding items to my invoice:
http://s7.postimg.org/l0q52l27v/error.png
As I can see in the picture, the problem is with some modifier and with "After.Update.sum". I use function that use "sum".
In my "server/collections/invoices_item.js"
I have:
InvoicesItem.after.update(function(userId, doc, fieldNames, modifier, options) {
var sum = 0; InvoicesItem.find({ invoiceId: doc.invoiceId }).map(function(item) { sum += item.amount; }); Invoices.update({ _id: doc.invoiceId }, { $set: { totalAmount: sum }});
});
Than I saw that problem could be with "totalAmount:sum". I use Chrome, so I tried "console.log()" to see if the page takes my collection.
And it doesn't.
I use Chrome, so I tried to see what the console will give me. I have something like this: http://s4.postimg.org/rusm4wx9p/fakturka.png
I did sth like that in my code on server side:
Meteor.publish("fakturka", function(invoiceId) {
return Invoices.find({_id:invoiceId,ownerId:this.userId}, {});
});
And did that on client side:
this.InvoicesNewInsertController = RouteController.extend({
template: "InvoicesNew",
yieldTemplates: {
'InvoicesNewInsert': { to: 'InvoicesNewSubcontent'}
},
onBeforeAction: function() {
/*BEFORE_FUNCTION*/
this.next();
},
action: function() {
if(this.isReady()) { this.render(); } else { this.render("InvoicesNew"); this.render("loading", { to: "InvoicesNewSubcontent" });}
/*ACTION_FUNCTION*/
},
isReady: function() {
var subs = [
Meteor.subscribe("invoices_item"),
Meteor.subscribe("invoiceeeee"),
Meteor.subscribe("customers"),
Meteor.subscribe("fakturka", this.params.invoiceId),
Meteor.subscribe("invoices_item_empty_faktura"),
Meteor.subscribe("invoices_itemss_faktura", this.params.invoiceId)
];
var ready = true;
_.each(subs, function(sub) {
if(!sub.ready())
ready = false;
});
return ready;
},
data: function() {
return {
params: this.params || {},
invoices_item: InvoicesItem.find({}, {}),
invoiceeeee: Invoices.find({}, {}),
customers: Customers.find({}, {}),
fakturka: Invoices.findOne({_id:this.params.invoiceId}, {}),
invoices_item_empty_faktura: InvoicesItem.findOne({_id:null}, {}),
invoices_itemss_faktura: InvoicesItem.find({invoiceId:this.params.invoiceId}, {})
};
/*DATA_FUNCTION*/
},
onAfterAction: function() {
}
});
I'm sorry for so much code, but I really want to solve that problem and I want to give so much info as I could. Please, help me to solve my problem.

After removing that code from: both/collections/invoices.js
Schemas={};
Schemas.Invoicess = new SimpleSchema({
invoiceNumber:{
type:Number
},
date_issued:{
type:Date
},
date_due:{
type:Date
},
customerId:{
type:String
},
totalAmount:{
type:String
}
});
Invoices.attachSchema(Schemas.Invoicess);
"fakturka" is visible. After adding that code - "fakturka" in undefined.