how I can run Javascript file in the flutter_webview_plugin. I try it with this.
flutterWebViewPlugin.evalJavascript("require('./index.js');");
But nothing happens.
when I try to run flutter code it's shows nothing
my index.Js file contains a simple alert statement
alert('hello world');
First, You used "require" function. this function is not implemented in javascript itself. it's a part of NodeJs. so that function will not work.
In order to load a js file into flutter, you should consider it as a text file and load it properly. So, you need to add the file to assets folder, add into pubspec file, then load it. read the full answer here
Second, you used evalJavascript. this function can be used in many different situations. but it will work only if you have a view panel.
Check below example:
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';
main() async {
String jsCode = await rootBundle.loadString('assets/javascript.js');
runApp(new MaterialApp(
home: LunchWebView(jsCode),
));
}
class LunchWebView extends StatelessWidget {
final String text;
LunchWebView(this.text);
#override
Widget build(BuildContext context) {
final FlutterWebviewPlugin flutterWebviewPlugin = FlutterWebviewPlugin();
flutterWebviewPlugin.launch('https://www.google.com');
flutterWebviewPlugin.evalJavascript(text);
return Container();
}
}
NOTE: : I didn't handle reloading and other exceptions. you should check if there is any webview object open and then call Lunch method.
Related
I am trying to parse some markdown before a page loads, so I have the following code:
<script context="module">
var markdown = require( "markdown" ).markdown;
export async function preload(page, session) {
var someMakrdown = '# Title'
var html = markdown.toHTML(someMakrdown)
return {post : html}
}
</script>
This fails with a 500 and the message: require is not defined
I have also tried using import in the following way:
<script context="module">
import {markdown} from 'markdown';
export async function preload(page, session) {
var someMakrdown = '# Title'
var html = markdown.toHTML(someMakrdown)
return {post : html}
}
</script>
This also fails with a 500 and the message Error resolving module specifier: util
I have got this to work by moving the code into a [slug].json.js file and calling that from within the preload, but is there a better way to do this?
One of the things that I've enjoyed so far about Svelte is keeping the HTML, CSS and JS together for each component. It just doesn't feel right that I need to call a seperate JS file to create JSON that can then be used.
It appears that the markdown module imports util, making it unsuitable for client-side use. Since preload functions run both server-side and client-side, that's no good. My suggestion would be to use a different library instead (I can recommend marked) and/or raise an issue on the markdown bug tracker.
Just in case someone needs a complete answer, here's how it looks like using marked, as proposed by Rich.
<script context="module">
import marked from 'marked';
let elem = '';
export function preload({ params, query }) {
elem = marked('# Marked in the server or/and browser');
}
</script>
<div>{#html elem}</div>
It'll run in the server and then, for subsequent navigation, in the browser.
I know this question maybe exist in stack overflow but I didn't get any good answers, and I hope in 2020 there is better solution.
In my react app I have a config JSON file, it contains information like the title, languages to the website etc..
and this file is located in 'src' directory
{
"headers":{
"title":"chat ",
"keys":"chat,asd ,
"description":" website"
},
"languages":{
"ru":"russian",
"ar":"arabic",
"en":"English"
},
"defaultLanguage":"ru",
"colors":{
"mainColor":"red",
"primary":"green",
"chatBackGround":"white"
}
}
I want to make my website easy to edit after publishing it, but after I build my app, I can't find that settings.json file there in build directory.
I find out that files in public directory actually get included to build folder, I tried to put my settings.JSON in public,
but react won't let me import anything outside of src directory
I found other solutions like this one but didn't work
https://github.com/facebook/create-react-app/issues/5378
Also I tried to create in index.html a global var like (window.JSON_DATA={}), and attach a JS object to it and import it to App.js, but still didn't work.
How can I make a settings JSON file, and have the ability to edit it after publishing the app?
Add your settings.json to the public folder. React will copy the file to the root of build. Then load it with fetch where you need it to be used. For example if you need to load setting.json to the App.js then do the next:
function App() {
const [state, setState] = useState({settings: null});
useEffect(()=>{
fetch('settings.json').then(response => {
response.json().then(settings => {
// instead of setting state you can use it any other way
setState({settings: settings});
})
})
})
}
If you use class-components then do the same in componentDidMount:
class CustomComponent extends React.Component {
constructor(props) {
super(props);
this.state = {settings: null};
}
componentDidMount() {
fetch('settings.json').then(response => {
response.json().then(settings => {
this.setState({settings: settings});
})
})
}
}
Then you can use it in render (or any other places of your component):
function App() {
...
return (
{this.state.settings && this.state.settings.value}
)
}
The easiest way would be to require() the file on the server during server side rendering of the html page and then inline the json in the html payload in a global var like you mentioned window.JSON_DATA={}. Then in your js code you can just reference that global var instead of trying to use import.
Of course this approach would require you to restart your server every time you make a change to the json file, so that it get's picked up. If that is not an option then you'll need to make an api call on the server instead of using require().
You may want to look at using npm react-scripts (https://www.npmjs.com/package/react-scripts) to produce your react application and build. This will package will create a template that you can put your existing code into and then give you a pre-configure build option that you can modify if you would like. The pre-configured build option will package your .json files as well. Check out their getting started section (https://create-react-app.dev/docs/getting-started/)
If you don't want to go that route, and are just looking for quick fix, then I would suggest change your json files to a JS file, export the JS object and import it in the files you need it since you seem to be able to do that.
//src/sampledata.js
module.exports = {
sample: 'data'
}
//src/example.jsx (this can also be .js)
const sampledata = require('./sampledata');
console.log(sampledata.sample); // 'data'
you can use 'Fetch Data from a JSON File'
according to link
https://www.pluralsight.com/guides/fetch-data-from-a-json-file-in-a-react-app
example
I am working on a project that requires using a js plugin. Now that we're using vue and we have a component to handle the plugin based logic, I need to import the js plugin file within the vue component in order to initialize the plugin.
Previously, this was handled within the markup as follows:
<script src="//api.myplugincom/widget/mykey.js
"></script>
This is what I tried, but I am getting a compile time error:
MyComponent.vue
import Vue from 'vue';
import * from '//api.myplugincom/widget/mykey.js';
export default {
data: {
My question is, what is the proper way to import this javascript file so I can use it within my vue component?
...
Include an external JavaScript file
Try including your (external) JavaScript into the mounted hook of your Vue component.
<script>
export default {
mounted() {
const plugin = document.createElement("script");
plugin.setAttribute(
"src",
"//api.myplugincom/widget/mykey.js"
);
plugin.async = true;
document.head.appendChild(plugin);
}
};
</script>
Reference: How to include a tag on a Vue component
Import a local JavaScript file
In the case that you would like to import a local JavaScript in your Vue component, you can import it this way:
MyComponent.vue
<script>
import * as mykey from '../assets/js/mykey.js'
export default {
data() {
return {
message: `Hello ${mykey.MY_CONST}!` // Hello Vue.js!
}
}
}
</script>
Suppose your project structure looks like:
src
- assets
- js
- mykey.js
- components
MyComponent.vue
And you can export variables or functions in mykey.js:
export let myVariable = {};
export const MY_CONST = 'Vue.js';
export function myFoo(a, b) {
return a + b;
}
Note: checked with Vue.js version 2.6.10
try to download this script
import * from '{path}/mykey.js'.
or import script
<script src="//api.myplugincom/widget/mykey.js"></script>
in <head>, use global variable in your component.
For scripts you bring in the browser way (i.e., with tags), they generally make some variable available globally.
For these, you don't have to import anything. They'll just be available.
If you are using something like Webstorm (or any of the related JetBrains IDEs), you can add /* global globalValueHere */ to let it know that "hey, this isn't defined in my file, but it exists." It isn't required, but it'll make the "undefined" squiggly lines go away.
For example:
/* global Vue */
is what I use when I am pulling Vue down from a CDN (instead of using it directly).
Beyond that, you just use it as you normally would.
I wanted to embed a script on my component and tried everything mentioned above, but the script contains document.write. Then I found a short article on Medium about using postscribe which was an easy fix and resolved the matter.
npm i postscribe --save
Then I was able to go from there. I disabled the useless escape from eslint and used #gist as the template's single root element id:
import postscribe from 'postscribe';
export default {
name: "MyTemplate",
mounted: function() {
postscribe(
"#gist",
/* eslint-disable-next-line */
`<script src='...'><\/script>`
);
},
The article is here for reference:
https://medium.com/#gaute.meek/how-to-add-a-script-tag-in-a-vue-component-34f57b2fe9bd
For anyone including an external JS file and having trouble accessing the jQuery prototype method(s) inside of the loaded script.
Sample projects I saw in vanilla JS, React and Angular were simply using:
$("#someId").somePlugin(options)
or
window.$("#someId").somePlugin(options)
But when I try either of those in my VueJS component I receive:
Error: _webpack_provided_window_dot$(...).somePluginis not a function
I examined the window object after the resources had loaded I was able to find the jQuery prototype method in the window.self read-only property that returns the window itself:
window.self.$("#someId").somePlugin(options)
Many examples show how to load the external JS file in VueJS but not actually using the jQuery prototype methods within the component.
How does the import statement actually work in JavaScript? I read the documentation and it says that it places exported code within the scope of the file. Does that mean that the code is copied over into the file where I type import?
For example - in library.js I have:
export {export function getUsefulContents(url, callback) {
getJSON(url, data => callback(JSON.parse(data)));
}
In main.js I have:
import { getUsefulContents} from 'library.js';
getUsefulContents('http://www.example.com',
data => { doSomethingUseful(data); });
This allows me to call getUsefulContents() in main.js. My question is, does main.js now have the contents that I exported from library.js?
Is using import the same as just having physically defined getUsefulContents() in main.js?
function getUsefulContents(url, callback) {
getJSON(url, data => callback(JSON.parse(data)));
}
getUsefulContents('http://www.example.com',
data => { doSomethingUseful(data); });
The main reason why I ask is because I want to know if using import will have an effect on main.js file size? Or is something else going on under the hood?
Thank you!
Depends on how you are using main.js. If you run it through a bundler, then the bundler will probably include library.js into main.js to pack it up into one file. In that case, the only advantage would be maintainability and ease of development because you are focused on the file you are working on. If you are simply running the import statement and deploying your application, the import statement won't affect the file size of main.js.
It just namespacing it within the file that you are importing it to so
any code from useful-library.js is included in the file, I visualize it this way
import { usefulCodeFromLibrary } from './useful-library.js';
((usefulCodeFromLibrary)=>{
// My excellent code
// Imported code doing it's job
usefulCodeFromLibrary.someHelperFunction()
}()
i was able to fire off an alert message from dart, but couldn't figure out how to call a function I wrote in another js file from dart. This would have been a great selling point if it was straight forward. I did see this post, which got me started, but i feel there must be a way, so please share the love if you figured it out.
Here's what I've done:
Add this to yaml file:
dependencies:
js:
hosted: js
Add import statement to top of dart file: import 'package:js/js.dart' as js;
Add this bit of code to show alert message
js.scoped(() {
js.context.alert("jump for joy!");
});
Here's the part which I think should work but doesn't: given that I have a javascript function doSomething(), I should be able to call
js.context.doSomething();
First add the js package as dependency in your pubspec.yaml :
dependencies:
js: any
Then you can use your own js function myFunc() like that :
import 'package:js/js.dart' as js;
main() {
js.context.myFunc();
}
js.context is an alias to javascript window.
See Using JavaScript from Dart: The js Library for more details.
Maybe my answer will be worth it for somebody, so that's why I'm posting a simple JS function call from Dart.
Add the js package dependency:
dependencies:
js: any
Create a JS file, let's say example.js:
function test() {
return 12+20;
}
Add the example.js above inside index.html with the <script src="..."> tag.
Interop the function above from JS to Dart:
#JS()
library t;
import 'package:js/js.dart';
#JS()
external int Test();
class MyOwn {
int get value => Test();
}
And, in AngularDart's TODOLIST — which is default component available —:
#override
Future<Null> ngOnInit() async => print(MyOwn().value);