Develop Reference

Javascript - prevent navigation during file upload

I have a vue component for video upload, where I am warning a user when he tries to navigate away during the video upload that he will lose the file if he does so, like this:
ready() {
window.onbeforeunload = () => {
if (this.uploading && !this.uploadingComplete && !this.failed) {
this.confirm('Are you sure you want to navigate away? Your video won't be uploaded if you do so!');
}
}
}
I am using sweetalert to alert the user about it. But how can I then make it stay on the same page, and prevent the navigation away before he confirms that he wants to navigate away?
This is the whole component:
<script>
function initialState (){
return {
uid: null,
uploading: false,
uploadingComplete: false,
failed: false,
title: null,
link: null,
description: null,
visibility: 'private',
saveStatus: null,
fileProgress: 0
}
}
export default {
data: function (){
return initialState();
},
methods: {
fileInputChange() {
this.uploading = true;
this.failed = false;
this.file = document.getElementById('video').files[0];
this.store().then(() => {
var form = new FormData();
form.append('video', this.file);
form.append('uid', this.uid);
this.$http.post('/upload', form, {
progress: (e) => {
if (e.lengthComputable) {
this.updateProgress(e)
}
}
}).then(() => {
this.uploadingComplete = true
}, () => {
this.failed = true
});
}, () => {
this.failed = true
})
},
store() {
return this.$http.post('/videos', {
title: this.title,
description: this.description,
visibility: this.visibility,
extension: this.file.name.split('.').pop()
}).then((response) => {
this.uid = response.json().data.uid;
});
},
update() {
this.saveStatus = 'Saving changes.';
return this.$http.put('/videos/' + this.uid, {
link: this.link,
title: this.title,
description: this.description,
visibility: this.visibility
}).then((response) => {
this.saveStatus = 'Changes saved.';
setTimeout(() => {
this.saveStatus = null
}, 3000)
}, () => {
this.saveStatus = 'Failed to save changes.';
});
},
updateProgress(e) {
e.percent = (e.loaded / e.total) * 100;
this.fileProgress = e.percent;
},
confirm(message) {
swal({
title: message,
text: null,
type: "warning",
showCancelButton: true,
cancelButtonText: "Cancel",
cancelButtonColor: '#FFF',
confirmButtonColor: "#2E112D",
confirmButtonText: "Yes, delete"
}).then(function(){
this.$data = initialState();
}.bind(this), function(dismiss) {
// dismiss can be 'overlay', 'cancel', 'close', 'esc', 'timer'
if (dismiss === 'cancel') { // you might also handle 'close' or 'timer' if you used those
// ignore
} else {
throw dismiss;
}
})
}
},
ready() {
window.onbeforeunload = () => {
if (this.uploading && !this.uploadingComplete && !this.failed) {
this.confirm('Are you sure you want to navigate away? Your video won't be uploaded if you do so!');
}
}
}
}
</script>

Mozilla documentation suggests
window.onbeforeunload = function(e) {
var dialogText = 'Dialog text here';
e.returnValue = dialogText;
return dialogText;
};
and also states that:
Since 25 May 2011, the HTML5 specification states that calls to window.alert(), window.confirm(), and window.prompt() methods may be ignored during this event. See the HTML5 specification for more details.
Source contains many other details regarding reasons and what to expect from modern browsers.
This question seems to be a duplicate of yours.
This answer suggests that to avoid weird browser behaviour you should set handler only when it's to prevent something (that is while navigating away should trigger a confirmation dialog)

But how can I then make it stay on the same page, and prevent the navigation away before he confirms that he wants to navigate away?
Add return false; to stop the event.
if (this.uploading && !this.uploadingComplete && !this.failed) {
this.confirm("Are you sure you want to navigate away? Your video won't be uploaded if you do so!");
return false; // <==== add this
}
return false; does 3 separate things when you call it :
event.preventDefault(); – It stops the browsers default behaviour.
event.stopPropagation(); – It prevents the event from propagating (or “bubbling up”) the DOM.
Stops callback execution and returns immediately when called.

Scope of 'this' on onTap and on popUp in ionic is 'undefined'

I want to show a popUp in ionic, which does not allow the user to exit when he hasn't entered some input. Right now I'm using this here:
public showOwnIdentifierPrompt() {
// Prompt popup code
var promptPopup = this.$ionicPopup.prompt({
title: this.floor_name,
template: `<input ng-model="$ctrl.customFloorName"></input>`,
scope: this.$scope,
buttons: [
{
text: this.cancel,
type: 'button-clear button-balanced',
onTap: function(e) {
// Cancel creation
return false;
}
},
{
text: this.save,
type: 'button-clear button-balanced',
onTap: () => {
// Create new floor
return true;
}
}
]
});
promptPopup.then((res) => {
if (res) {
this.addNewFloor(this.customFloorName);
}
})
}
In the save onTap() event handler, I would like to access this.customFloorName from my class, to decide whether the user entered input. But it is always undefined. What can I do?

You can get value on Save with below code :
var value = this.scope.$ctrl.customFloorName;

Google Chrome extension to close notification after user click

The Chrome extension works fine. My problem is that the notification closes in 7 seconds. I want for the user click to close the notification.
function engine(){
var latestId;
var ids;
var messages = [];
var newmessage = [];
$.get('http://localhost/site/json.php',function (data){
var json = $.parseJSON(data);
messages = json;
ids = json[0].id;
if(latestId == ids){
//no update
}else if(latestId === undefined){
var run = {
type: "basic",
title: "Title",
message: "Some message",
iconUrl : "icon.png",
};
chrome.notifications.create(run);
}
});
}

First create your notification and give it a notificationID parameter to close it later.
var notification = {
type:"basic",
title:"News From Us!",
message:"Google Chrome Updated to v50!",
iconUrl:"assets/images/icon.png"
};
chrome.notifications.create("notfyId",notification);
On notification click you can close notification using its id (which is "notfyId")
function forwardNotfy(){
chrome.notifications.clear("notfyId");
window.open(url); //optional
}
chrome.notifications.onClicked.addListener(forwardNotfy);
Now, when you click your notification it'll close.

This feature is currently only implemented in the beta channel, and not in the latest version of chrome. See here for details.
When it is implemented, you will be able to use requireInteraction : True like:
var run = {
type: "basic",
title: "Title",
message: "Some message",
iconUrl : "icon.png",
requireInteraction : True,
}
to implement this.

You can use notification.close();:
setTimeout(function() {
notification.close();
}, 2000);
Demo:
// request permission on page load
document.addEventListener('DOMContentLoaded', function () {
if (Notification.permission !== "granted")
Notification.requestPermission();
});
function notifyMe() {
if (!Notification) {
alert('Desktop notifications not available in your browser. Try Chromium.');
return;
}
if (Notification.permission !== "granted")
Notification.requestPermission();
else {
var notification = new Notification('Notification title', {
icon: 'http://cdn.sstatic.net/stackexchange/img/logos/so/so-icon.png',
body: "Hey there! You've been notified!x",
});
notification.onclick = function () {
window.open("http://stackoverflow.com/a/13328397/1269037");
};
setTimeout(function() {
notification.close();
}, 2000);
}
}
<button onclick="notifyMe()">
Notify me!
</button>
JSBin Demo

notification.close() is used to close any notification.
For more information please see the below code-
To create the notification:
var notification = new Notification('OnlineOfferPrice', {
icon: 'icon.png',
body: "Test Message",
});
If you want to perform operation on notification click please use the below code. After your business logic it will automatically close-
notification.onclick = function () {
//write your business logic here.
notification.close();
};
If notification is not clicked and you want to close it automatically after 6 seconds-
setTimeout(function() { notification.close(); }, 6000);

Firefox Extension trouble using port.emit and port.on

I can't seem to get port.emit working correctly with my Firefox extension. From the init() function in popup.js the messages are correctly sent to main.js using addon.port.emit. Once they've been sent, the giveStorage message is correctly received in popup.js. However, this only works correctly when the original message is sent in the init function.
When I try sending the messages using using the jQuery change listener, the logs "Storage has been set." and "Sending storage to popup.js" come through, so popup.js is just not receiving it, but I have no idea why not. Only messages are logged correctly when ran from the init function.
If anyone has any ideas, or if you need any more information, please let me know and I'll see what I can do. Any help is greatly appreciated!
main.js
panel.port.on("setStorage", function (text) {
console.log("Storage has been set.");
ss.storage[text[0]] = text[1];
})
panel.port.on("getStorage", function (text) {
console.log("Sending storage to popup.js");
panel.port.emit("giveStorage", [text, ss.storage[text]])
})
popup.js
function init(){
$(".panel").hide();
addon.port.emit("getStorage", "username");
addon.port.emit("getStorage", "volume");
setInterval(function(){following();}, 60000);
}
addon.port.on("giveStorage", function (text) {
console.log("Message received from main.js");
if (text[1] !== null) {
if (text[0] === "username") {
username = text[1];
$('#menuFollowing').click();
}
else if (text[0] === "volume"){
volume = text[1];
$("#volume").val(volume);
$('#volumeValue').empty();
$('#volumeValue').append('Volume: ' + volume);
}
}
})
$('#volume').change(function(){
volume = $('#volume').val();
addon.port.emit("setStorage", ["volume", volume]);
addon.port.emit("getStorage", "volume");
});
Complete main.js
var { ToggleButton } = require('sdk/ui/button/toggle');
var panels = require("sdk/panel");
var self = require("sdk/self");
var ss = require("sdk/simple-storage");
var notifications = require("sdk/notifications");
var panel = panels.Panel({
width: 500,
height: 500,
contentURL: self.data.url("popup.html"),
onHide: handleHide,
});
var button = ToggleButton({
id: "hitbox-plus",
label: "hitbox Plus",
icon: {
"16": "./icon16.png",
"48": "./icon48.png",
},
onChange: handleChange,
});
function handleChange(state) {
panel.contentURL = self.data.url("popup.html");
if (state.checked) {
panel.show({
position: button
});
}
}
function handleHide() {
button.state('window', {checked: false});
}
panel.port.on("getStorage", function (text) {
console.log("Sending storage to popup.js");
panel.port.emit("giveStorage", [text, ss.storage[text]])
})
panel.port.on("setStorage", function (text) {
console.log("Storage has been set.");
ss.storage[text[0]] = text[1];
})

How can I remove a whole IndexedDB database from JavaScript?

How can one remove a whole IndexedDB database from JavaScript, as opposed to just an object store? I'm using the IndexedDB shim, which may use WebSQL as its backend.
I'd mainly like to know how to do this for the PhantomJS (headless) browser, although Chrome, Safari (on iPad) and IE10 are other important browsers.

As far as I can tell, one should use indexedDB.deleteDatabase:
var req = indexedDB.deleteDatabase(databaseName);
req.onsuccess = function () {
console.log("Deleted database successfully");
};
req.onerror = function () {
console.log("Couldn't delete database");
};
req.onblocked = function () {
console.log("Couldn't delete database due to the operation being blocked");
};
I can confirm that it works with PhantomJS 1.9.0 and Chrome 26.0.1410.43.

I found that the following code works OK but to see the DB removed in the Chrome Resources Tab I have had to refresh the page.
Also I found I had problems with the Chrome debug tools running while doing transactions. Makes it harder to debug but if you close it while running code the code seems to work OK.
Significant also is to set a reference to the object store when opening the page.
Obviously the delete part of the code is in the deleteTheDB method.
Code derived from example provided by Craig Shoemaker on Pluralsight.
var IndDb = {
name: 'SiteVisitInsp',
version: 1000,
instance: {},
storenames: {
inspRecords: 'inspRecords',
images: 'images'
},
defaultErrorHandler: function (e) {
WriteOutText("Error found : " + e);
},
setDefaultErrorHandler: function (request) {
if ('onerror' in request) {
request.onerror = db.defaultErrorHandler;
}
if ('onblocked' in request) {
request.onblocked = db.defaultErrorHandler;
}
}
};
var dt = new Date();
var oneInspRecord =
{
recordId: 0,
dateCreated: dt,
dateOfInsp: dt,
weatherId: 0,
timeArrived: '',
timeDeparted: '',
projectId: 0,
contractorName: '',
DIWConsultant: '',
SiteForeman: '',
NoOfStaffOnSite: 0,
FileME: '',
ObservationNotes: '',
DiscussionNotes: '',
MachineryEquipment: '',
Materials: ''
};
var oneImage =
{
recordId: '',
imgSequence: 0,
imageStr: '',
dateCreated: dt
}
var SVInsp = {
nameOfDBStore: function () { alert("Indexed DB Store name : " + IndDb.name); },
createDB: function () {
openRequest = window.indexedDB.open(IndDb.name, IndDb.version);
openRequest.onupgradeneeded = function (e) {
var newVersion = e.target.result;
if (!newVersion.objectStoreNames.contains(IndDb.storenames.inspRecords)) {
newVersion.createObjectStore(IndDb.storenames.inspRecords,
{
autoIncrement: true
});
}
if (!newVersion.objectStoreNames.contains(IndDb.storenames.images)) {
newVersion.createObjectStore(IndDb.storenames.images,
{
autoIncrement: true
});
}
};
openRequest.onerror = openRequest.onblocked = 'Error'; //resultText;
openRequest.onsuccess = function (e) {
//WriteOutText("Database open");
IndDb.instance = e.target.result;
};
},
deleteTheDB: function () {
if (typeof IndDb.instance !== 'undefined') {
//WriteOutText("Closing the DB");
IndDb.instance.close();
var deleteRequest = indexedDB.deleteDatabase(IndDb.name)
deleteRequest.onblocked = function () {
console.log("Delete blocked.");
}
deleteRequest.onerror =
function () {
console.log("Error deleting the DB");
//alert("Error deleting the DB");
};
//"Error deleting the DB";
deleteRequest.onsuccess = function () {
console.log("Deleted OK.");
alert("*** NOTE : Requires page refresh to see the DB removed from the Resources IndexedDB tab in Chrome.");
//WriteOutText("Database deleted.");
};
};
}
}