Develop Reference

Best way to animate a constant (unknown) data flow with Vue.js?

I'm currently running into a problem trying to get a smooth animation.
I'm using vue + electron, with the main processes sending data to the renderer process at about 16-33ms (30-60fps). When I receive the data in my component, I update the data property and it is bound to the style property of the element. This does work, but there's quite a bit of jitter. I'm curious if there's a better way to handle this. Is there something similar to requestAnimationFrame()? Thank you.
Simplified example:
<template>
<div>
<img :style={'transform': `translate(${x}%, ${y}%)} src=""></img>
</div>
</template>
<script>
data: function () {
return {
x: 50,
y: 50
}
},
mounted () {
// this is coming every ~16-33ms
this.$electron.ipcRenderer.on('data', (e, data) => {
this.x = data.x
this.y = data.y
})
}
</script>

You created a multi layered issue there.
Electron IPC's are slow, the reason for that is that they serialize/de-serialize JSON objects and not buffer, also the main and render process have to sync. A simple solution to this specific issue is to write an preload script and bring your logic from the main into the render thread. No need for IPC, no serialization, direct access to NodeJS and any native node module.
For constant animations on values CSS animations are often lacking on low-end PC's they tend to interrupt animations, so it's advisable to use a framework for tweening/animation an example of this is anime.js or this self writting vue example from the vue docs https://v2.vuejs.org/v2/guide/transitioning-state.html#Dynamic-State-Transitions
I hope this brings you on the right track ;)

Using eval to dynamically render JSX served from backend

I'm working on a React frontend that gets data from a python JSON API. One section of my website has premium content and is reserved for paying users; currently I ensure that other users don't have access to it by fetching the content as a JSON object and converting it to JSX on the frontend according to a certain convention. For example:
{
{ 'type': 'paragraph', 'value': 'some text'},
{ 'type': 'anchor', 'href': 'some url', 'value': 'some description'}
}
would be rendered as :
<p>some text</p>
some description
Not surprisingly, things started to get pretty complicated as the content began to get more structured, simple things like making part of the text bold require a disproportional amount of effort.
As a potential solution, I had this idea: instead of sending the content as an object and parsing it, why not send a string of JSX and evaluate it on the frontend?
I started like this:
import * as babel from "#babel/standalone";
export function renderFromString(code) {
const transformed_code = babel.transform(code, {
plugins: ["transform-react-jsx"]
}).code;
return eval(transformed_code);
}
I imported this function in my premiumContent page and tried passing a complete component as a string (with import statements, etc) but got errors because the modules can't be found. I assumed this happens because the code is being interpreted by the browser so it doesn't have access to node_modules?
As a workaround, I tried passing only the tags to renderFromString and call it in the context of my component where all the modules are already imported :
import * as babel from "#babel/standalone";
export function renderFromString(code, context) {
const _es5_code = babel.transform(code, {
plugins: ["transform-react-jsx"]
}).code;
return function() {
return eval(_es5_code);
}.call(context);
}
This also failed, because it seems that eval will still run from the local context.
Finally, I tried doing the same as above but executing eval directly in my component, instead of from my function .This works as a long as I store "React" in a variable : import ReactModule from "react";const React = ReactModule, otherwise it can't be found.
My questions are:
Is there any way I can make my first two approaches work?
I know eval is considered harmful, but since the content is always completely static and comes from my own server, I don't see how this wouldn't be safe. Am I wrong?
Is there a better solution for my problem? That is, a way to safely deliver structured content to only some users without changing my single page app + JSON api setup?

The best solution for this is React server-side rendering.
Since you need markup that is client-side compatible but at the same time dynamically generated through React, you can offload the markup generation to the server. The server would then send the rendered HTML to the client for immediate display.
Here's a good article about React SSR and how it can benefit performance.

<require> inside a globalResource component called with enhance in Aurelia

So, I'm trying to setup Aurelia in my Angular 1 web application so I can slowly upgrade. I need to do that since the application is too big and migrating everything at once would be impossible.
So, in my Aurelia folder I created a component folder with two components (aurelia-component.js and another-component.js with their views aurelia-component.html and another-component.html), I won't put the javascript as they are just two classes with one property, the html for both is the same, the only thing that changes is the text property value so I can differentiate them:
<template>
<div>${text}</div>
</template>
My entry point main.js looks like this:
export function configure(aurelia) {
aurelia.use
.basicConfiguration()
.developmentLogging()
.globalResources('components/aurelia-component')
.globalResources('components/another-component');
//window.aurelia = aurelia;
aurelia.start()
.then(a => {
window.aurelia = a;
});
}
As you can see, this puts Aurelia in the window object so I can access it from my Angular app, I'll improve this later.
In my angular app I have this directive:
'use strict';
function AureliaContainer() {
function Link($scope, element, attrs) {
window.aurelia.enhance(element[0]);
}
//
return {
restrict: 'A',
link: Link
};
}
module.exports = AureliaContainer;
I set this up in my app root with:
app.directive('aureliaContainer', require('./directives/aurelia.container'));
And in my Angular View I have these divs with my directive that calls the enhance function from Aurelia:
<div aurelia-container>
<aurelia-component></aurelia-component>
</div>
<div aurelia-container>
<another-component></another-component>
</div>
The reason I have two aurelia-container in the html is that I know I'll have to have more than one when I'm migrating the application.
And this works fine, both components load normally in the screen.
The problem is when I try to call another component from within one of those components.
What I did was, I created a new component called test-component.js with its view test-component.html. The html for this is just:
<template>
<h1>Header</h1>
</template>
And then, from the aurelia-component.html I called it using:
<template>
<require from="./test-component"></require>
<div>${text}</div>
<test-component></test-component>
</template>
Now, when I load the page, the test-component actually loads but the <div>${text}</div part of aurelia-component doesn't and I get this error in the console:
Uncaught (in promise) TypeError: Cannot read property 'behaviorInstructions' of undefined
I really don't understand why this error is happening, I should be able to load a custom element from within another one normally, shouldn't I. Or is there a limitation when you use enhance?
I also tried to use setRoot in both divs with no success, just one of them is loaded.
Maybe there's a better approach for this?
Again, I can't migrate my entire application at once, it's just no feasible.
Thanks in advance for the help.

First off, I know nothing about progressive enhancement in Aurelia. And cannot comment about its suitability for your scenario.
But I am wondering if maybe you missed some Au dependencies (like binding or templating?)
http://aurelia.io/hub.html#/doc/article/aurelia/framework/latest/app-configuration-and-startup/8
aurelia.use
.defaultBindingLanguage()
.defaultResources()
.developmentLogging()
.globalResources('resources/my-component');
That might explain why it fails when you want it to render a template?

Returning dom element from json

I have a JSON like this:
{
"HOME_VIEW_CONTENT": {
"header": "<div>Hello <span className='someClass'>world!</span></div>",
"ingress": "Hello moon!"
}
}
then in react I have this code:
{content.header}
{content.ingress}
And this works, but i'm getting the div out as a string (naturally).
Is there a plugin or an easy way to convert the string with the div to an div object without using dangerouslyInsertInnerHtml in react?
I am using a webpack + react setup so i might use a loader? or Is there a react method for doing this?

React escapes the HTML to prevent XSS.
If you really want to render HTML, you can use dangerouslySetInnerHTML:
dangerouslySetInnerHTML={{__html: this.state.actions}}
React has this syntax so that you don't accidentally render text as HTML and introduce XSS bugs.
This is from the docs, i have not tested this as i did not need it so far.

How to inject 3rd party javascript in Ember.js template?

I'm trying to utilize two 3rd party widgets on a website however cannot quite figure out how to get Ember.js to cooperate. I found lots on Views and have found that they're deprecated now and Components seem the way to go however I'm not sure how to make this work...
I have various city-based templates that require:
<script type="text/javascript" src="http://www.topix.net/iframe/city/atco-nj?js=1"></script>
and one other that looks like this:
<script>document.write('<script src="... + Math.random() + ..."></script>');</script>
How would I do this with Components or a better alternative!?

For this you don't really need a component, you could just create a template and inject it wherever you need it. However I'm not 100% what are city based templates but just to output html you can just use a template template / helper:
using a template (known as partial):
run (if using ember cli , if not just create the template file somewhere, again assuming you have some way you're compiling templates on the server)..
ember g partial inject_city
then:
//inject_city.hbs
<script type="text/javascript" src="http://www.topix.net/iframe/city/atco-nj?js=1"></script>
then in your main template:
{{partial 'inject_city'}}
Further reading: http://guides.emberjs.com/v1.10.0/templates/writing-helpers/
using a helper (notice to return html you must use the safestring)
Ember.Handlebars.helper('injectScript', function(value, options) {
return new Ember.Handlebars.SafeString("<script>document.write('<script src="... + Math.random() + ..."></script>');</script> );
});
In version 1.13.0 and above the syntax is different:
import Ember from "ember";
export default Ember.Helper.helper(function(params) {
return Ember.String.htmlSafe(`<b>${params[0]}</b>`);
});
(Notice you should generate a helper, wrap it with Helper.helper and return Ember.String.htmlSafe).
further reading: http://guides.emberjs.com/v1.10.0/templates/writing-helpers/
However the best way is to include libraries in your ember build / build your own component from by using the building blocks, and not just include a whole script..The ember documentation explains about components pretty well and ember-cli docs explain how to include third party libs..
Best of luck!

I got this to work by making a component. I had the same sort of problem, I wanted to draw some pie charts at load time of the page using charts.js
SO i defined the charts and ran the js to create them in a component.
heres the component 'js-charts':
export default Ember.Component.extend({
didInsertElement: function() { insert script and or methods to run }
});
This will always trigger because of the didInsertElement.
and in the template of the page your rendering just add {{js-charts}} component