I am learning mongodb with meteor js so dont have much knowledge of both mongodb and meteor.
Below is the js code:
import { Template } from 'meteor/templating';
import { Dbs } from '../lib/collections.js';
import './main.html';
Template.body.helpers({
/*temp1:[
{text:'my data1'}'
{text:'my data1'}
]*/
dbs(){
return Dbs.find({'user_id':'p123'});
}
});
Basically i just want to pass user id in a textbox and based on it,i want to display the other details of user.In above code i am passing it manually and its working.anyone suggest me what should i do here ?
You can attach to the template instance a ReactiveVar that you will update with an event.
Then use it inside the helper, so the helper will re-execute everytime the value change:
Template.myTemplate.onCreated(function() {
this.currentTextBox = new ReactiveVar();
});
Template.myTemplate.events({
"keyup .js-my-textbox"(event, instance) {
// This event is executed when you type in an input with the class "js-my-textbox"
instance.currentTextBox.set(event.target.value);
},
});
Template.myTemplate.helpers({
dbs() {
const instance = Template.instance();
return Dbs.find({'user_id': instance.currentTextBox.get() });
},
});
EDIT:
Example of what could be the html part:
<template name="myTemplate">
<input type="text" placeholder="Search" class="js-my-textbox">
{{#each db in dbs}}
<-- Do what you want, example: -->
<p>{{db.myField}}</p>
{{/each}}
</template>
First You Create Event Function Template.body.events({}) to access text .Then store variable to use Meteor Session. Then Variable easily access helpers.If session changes variable will be changed.
Related
I'm trying to prevent a template helper to be rerun when it is unnecessary. I made a simple application to illustrate this behavior:
Let's say I want to display some items that contain only a title and a description.
<template name="Tests">
{{#each items}}
{{> TestsItems}}
{{/each}}
</template>
<template name="TestsItems">
<div class="title">{{title}}</div>
<div class="description">{{description}}</div>
</template>
I have autopublish enabled.
Template.Tests.helpers({
items: function () {
return Items.find();
}
});
Template.TestsItems.helpers({
description: function () {
// I'm using this helper to do some updates
// on a jQuery plugin when the description field change.
// see example 1: https://github.com/avital/meteor-ui-new-rendered-callback/
console.log("The description is run");
return this.description;
}
});
When a new update is made on the title field only, you can see that the description helper is rerun. What I'm trying to achieve is to only rerun this helper when there is a new value for the description field and not every time a field has changed in the document.
As {{#constant}} and {{#isolate}} are deprecated, how can I get this behavior in the latest Meteor versions?
Note 1: Create a new subtemplate including the description does not fix the problem.
I would avoid side effects in template helpers. Instead I would use an autorun:
Template.TestItems.rendered = function () {
var _id = this.data._id;
this.autorun(function () {
// Select only the description field, so that we only
// trigger a re-run if the description field changes
var description = Items.findOne(_id, {fields: {description: 1}}).description;
// update the JQuery plugin
});
}
I have the following templates (.html) with their respected managers (.js files):
adminManageCategories
adminAddCategory
adminUpdateCategory
Consider the following:
<template name="adminManageCategories">
{{#each category}}
<div class="clickme">{{title}}</div>
{{/each}}
{{> adminUpdateCategory}}
</template>
Notice the {{> adminUpdateCategory}} is outside of the iteration. This is also a form, and I want to keep it on the same page.
And admin_manage_categories.js
Template.adminManageCategories.events({
"click .clickme": function(event) {
event.preventDefault();
console.log(this._id);
}
});
Notice the console.log() function, which works, as the template manager is smart enough to know the ID of the item that was clicked.
What I want to do is load this items values into the form when clicked. My example above is slim, but in my real data I have a title, sort order, among other things.
So my question is, what is the proper way to pass the _id from the adminManageCategories template to the adminUpdateCategory template, which is the form?
I can hack at this with JavaScript and make things happen, but I think I'm missing a "Meteor way" of doing things.
You need to use a ReactiveVar to store the currently clicked item.
First you need to run meteor add reactive-var, as it's not a package added by default in a standard meteor web app.
JS:
Template.adminManageCategories.created=function(){
// instantiate the reactive-var in the created callback
// we store it as a property of the template instance
this.currentItemId=new ReactiveVar(null);
};
Template.adminManageCategories.helpers({
// this helper reactively returns the currently clicked item
currentItem:function(){
// retrieve the reactive-var from the template instance...
var currentItemId=Template.instance().currentItemId.get();
// ...to fetch the correct collection document
return Items.findOne(currentItemId);
}
});
Template.adminManageCategories.events({
"click .clickme": function(event,template) {
event.preventDefault();
// assign the correct item id to the reactive-var attached to this template instance
template.currentItemId.set(this._id);
}
});
HTML:
<template name="adminManageCategories">
{{#each category}}
<div class="clickme">{{title}}</div>
{{/each}}
<p>Current item title is : {{currentItem.title}}</p>
{{! pass the currentItem as a parameter to your child template this will be
accessible as {{item}} in the HTML and "this.item" in JS helpers or
"this.data.item" in created/rendered/destroyed callbacks}}
{{> adminUpdateCategory item=currentItem}}
</template>
EDIT:
When I initialize the reactive-var in the created callback, I set it to null, this means that until one item is clicked, the helper will return null too and when you'll try to access this.item._id in the adminUpdateCategory this will fail.
The simplest way to solve this issue is maybe to not initialize the variable to null but to the first item in the collection.
Template.adminManageCategories.created=function(){
var firstItem=Items.findOne({},{
sort:{
sortedField:1
}
});
this.currentItemId=new ReactiveVar(firstItem && firstItem._id);
};
There may still be a case when you have 0 items in the collection, so you'll probably end up having to guard against the existence of the item in the JS.
Template.adminUpdateCategory.helpers({
itemProperty:function(){
return this.item && this.item.property;
}
});
Is it possible for a parent Meteor template to access a subtemplate directly? Ideally, I'd like to use templates a widgets with an API. I was hoping for something like this:
mypage.html
<template name="myPage">
<div class="widgetContainer"></div>
<button>submit</button>
</template>
mypage.js
Template.myPage.rendered = function(){
this.myWidgetInstance = UI.render(Template.myWidget)
UI.insert(this.myWidgetInstance, $('.widgetContainer')[0]);
}
Template.myPage.events({
'click button': function(e, template){
// I don't want this logic to live inside of mywidget.js.
// I also don't want this template to know about the <input> field directly.
var val = template.data.myWidgetInstance.getMyValue();
}
});
mywidget.html
<template name="myWidget">
<input></input>
</template>
mywidget.js
Template.myWidget.getValue = function(){
return this.$('input').val();
}
The above doesn't work because myWidgetInstance.getMyValue() doesn't exist. There doesn't appear to be a way for external code to access template helper functions on an instance.
Is anyone using Meteor templates in the way I'm trying to use them above? Or is this better suited for a separate jQuery widget? If so, it'd be a shame because I still want my widget template to benefit from the features Meteor provides.
It is possible to access subtemplate helper function.
Your example will work once you apply few fixes:
fix 1 : getValue() instead of getMyValue()
Template.myPage.events({
'click button': function(e, template){
// I don't want this logic to live inside of mywidget.js.
// I also don't want this template to know about the <input> field directly.
var val = template.myWidgetInstance.getValue();
console.log(val);
}
});
fix 2 : $('input').val(); instead this.$('input').val();
Template.myWidget.getValue = function(){
return $('input').val();
}
fix 3 : <input> should have no close tag.
<template name="myWidget">
<input type="text" value="sample value">
</template>
In Iron-router, we can pass the data to a page in the data field. For example:
Router.map(function () {
this.route('myroute', {
path: '/route',
template: 'myTemplate',
data: function () {
return {
title: getTitle(),
description: getDescription(),
}
}
});
});
In the template, title and description are actually some value passed to subtemplates:
<template name="myTemplate">
{{> titleTemplate title}}
{{> descriptionTemplate description}}
</template>
Since the data field in the iron-router is reactive, whenever a session variable change, the data field is recalculated.
In this case, however, the session variable in getTitle function only changes the template "titleTemplate", and the session variable in getDescription() function only changes the template "descriptionTemplate".
If the session variable in the getTitle() function changes, I would like to only execute the getTitle() function, and do not execute the getDescription() function. If possible, I would also like to only render the "titleTemplate" and do not render "descriptionTemplate".
I wonder whether that is possible. If this is not the right way of writing the Meteor application, what is a better way to do it?
Thanks.
This is an interesting situation. Despite the fact that the getTitle and getDescription functions may be dependent on completely different reactive variables, they will both be recomputed whenever either one of them changes.
One possible solution is to pass the functions themselves instead of the result of calling the functions. That may or may not be convenient depending on how they are used in the sub-templates, but it will prevent them from both being run every time. Here is a simple example:
<template name="myTemplate">
{{> titleTemplate title}}
{{> descriptionTemplate description}}
</template>
<template name="titleTemplate">
<p>{{excitedTitle}}</p>
</template>
<template name="descriptionTemplate">
<p>{{this}}</p>
</template>
var getTitle = function() {
console.log('computed title');
return Session.get('title');
};
var getDescription = function() {
console.log('computed description');
return Session.get('description');
};
Router.map(function() {
this.route('home', {
path: '/',
template: 'myTemplate',
data: function() {
return {
title: getTitle,
description: getDescription
};
}
});
});
Meteor.startup(function() {
Session.setDefault('title', 'title1');
Session.setDefault('description', 'description1');
});
Template.titleTemplate.excitedTitle = function() {
return "" + (this.toUpperCase()) + "!";
};
From the console you can change the session variables (title and description) and you will see that only one function will be run at a time. I hope that helps.
One way to solve this is to not use the data context, but just use template specific helpers. Since I don't know what your getTitle and getDescription function do, I can't tell whether that is an option for you. It depends on whether you need to use the this object in those functions and need this to refer to the route object or not. If not, then the following seems like the better solution:
JS:
Router.map(function () {
this.route('myroute', {
path: '/route',
template: 'myTemplate'
});
});
Template.myTemplate.title = getTitle;
Template.myTemplate.description = getDescription;
HTML:
<template name="myTemplate">
{{> titleTemplate title}}
{{> descriptionTemplate description}}
</template>
If I have an {{# each}} binding in Meteor, and I want to update a property on only one instance of the template inside the #each. How would I do that? I've tried setting a value on the "template" object inside the events map, but that doesn't seem to be reactive. I've also tried binding to a Session property, but that will cause every instance to update instead of just the one I want...
for example:
{{#each dates}}
{{> dateTemplate}}
{{/each}}
<template name="dateTemplate">
{{date}}
<span style="color: red;">{{errorMsg}}</span> <--- how do i update errorMsg?
</template>
Template.dateTemplate.events({
'click': function(event, template) {
template.errorMsg = 'not valid'; <--- this doesn't do anything
}
});
EDIT TO ADDRESS ANSWER BELOW:
Template.dateTemplate.events({
'click': function(event, template) {
template.errorMsg = function() { return 'not valid';} <--- this also doesn't do anything
}
});
You don't have to use handlebars for this, because its not something that needs reactivity to pass the message through, reactive variables work best with db data, or data that would be updated by another client over the air.
You could use JQuery (included by default) to update it, it can also get a bit fancier:
<template name="dateTemplate">
{{date}}
<span style="color: red;display: none" class="errorMessage"></span>
</template>
Template.dateTemplate.events({
'click': function(event, template) {
$(template.find('.errorMessage')).html('Your Error Message').slideDown();
}
});
Ive edited it so the error is hidden by default, and slides down with an animation
I'm experimenting handling this by passing a different reactive object to each instance of the template. Then the template can bind to the reactive object (which is unique per instance) and we don't have any extra boilerplate.
It ends up looking like this:
Initial render:
Template.firstTemplateWithPoll(ContextProvider.getContext())
Template.secondTemplateWithPoll(ContextProvider.getContext())
// (I actually pass getContext an identifier so I always get the same context for the same template)
JS:
Template.poll.events = {
'click .yes' : function() {
this.reactive.set('selection', 'yes');
},
'click .no' : function() {
this.reactive.set('selection', 'no');
}
};
Template.poll.selection = function(arg) {
return this.reactive.get('selection');
}
Template:
<template name="poll">
<blockquote>
<p>
Your selection on this poll is {{selection}}
</p>
</blockquote>
<button class='yes'>YES</button>
<button class='no'>NO</button>
</template>
template.errorMsg should be a function that returns your error.
Template.dateTemplate.events({
'click': function(event, template) {
template.errorMsg = function() { return 'not valid'; };
}
});