I want to be able to set a function onbroadcast in SpeechRecognition after I create a new SpeechRecognition object so that I can call this function internally if certain conditions are met.
I would like to be able to set it in the same way that you would set something like onerror in webkitSpeechRecognition. When I look at onerror in the Developer Tools it looks like it might be done via some sort of getter/setter like what is described here but I can't be certain.
Is this possible?
recognition.js:
var SpeechRecognition = function () {
var recognitionObject = new webkitSpeechRecognition();
recognitionObject.onresult = function (event) {
if(event.results.length > 0) {
if (onbroadcast !== null && onbroadcast === 'function') {
onbroadcast('there are results');
}
}
}
recognitionObject.onerror = function (event) {
console.log(event);
}
recognitionObject.onend = function (event) {
console.log(event);
}
recognitionObject.start();
}
SpeechRecognition.prototype.onbroadcast = null;
main.js:
var sr = new SpeechRecognition();
sr.onbroadcast = function(msg) {
document.getElementById('id') = msg;
}
You need to refer to onbroadcast as a property of your instance (this.onbroadcast). It doesn't magically become available as a variable inside the constructor scope.
function SpeechRecognition() {
var self = this; // a reference to the instance
var recognitionObject = new webkitSpeechRecognition();
recognitionObject.onresult = function (event) {
if (event.results.length > 0 && typeof self.onbroadcast === 'function') {
self.onbroadcast('there are results');
// ^ a property access
}
};
recognitionObject.onerror = recognitionObject.onend = function (event) {
console.log(event);
};
recognitionObject.start();
}
Related
I have this object that carries some functions. At some point, I would like to hold an event and call this object within that event, but only if you call this object using this, is there any way to call it without this?
I haven't tried anything yet, because I couldn't find anything to help.
const cantaVideoModal = {
click: null,
target: null,
urlVideo: null,
config: function (c) {
this.click = c.click;
this.target = c.target;
this.urlVideo = c.urlVideo;
this.init();
},
init: function () {
this.click = (this.click) ? document.querySelector(this.click) : null;
this.target = (this.target) ? document.querySelector(this.target) : null;
let btnCloseVideo = document.querySelector('[data-close-modal]');
if(btnCloseVideo){
btnCloseVideo.addEventListener('click', function(){
//call modalAction object here using this
})
}
},
modalAction: function (act) {
let elementClick = this.click;
let elementtarget = this.target;
if (elementClick) {
elementClick.addEventListener('click', function (e) {
e.preventDefault();
if (elementtarget) {
if(act === "toggle")
elementtarget.classList.toggle('in');
if(act === "show")
elementtarget.classList.add('in');
if(act === "hide")
elementtarget.classList.remove('in');
}
})
}
}
}
The reason you cannot use this is because you are in a function inside a addEventListener. I'm not sure why, but you can create a new object that refer to the current object, which can be used inside the annonymous functon. For more information on why you can't use this inside a addEventListener see this answer
const cantaVideoModal = {
click: null,
target: null,
urlVideo: null,
config: function (c) {
this.click = c.click;
this.target = c.target;
this.urlVideo = c.urlVideo;
this.init();
},
init: function () {
this.click = (this.click) ? document.querySelector(this.click) : null;
this.target = (this.target) ? document.querySelector(this.target) : null;
let btnCloseVideo = document.querySelector('[data-close-modal]');
if(btnCloseVideo){
// we create a new variable that refer to the current content.
var self = this
btnCloseVideo.addEventListener('click', function() {
//call modalAction object here using self.
self.modalAction(/* some parameters */);
})
}
},
modalAction: function (act) {
let elementClick = this.click;
let elementtarget = this.target;
if (elementClick) {
elementClick.addEventListener('click', function (e) {
e.preventDefault();
if (elementtarget) {
if(act === "toggle")
elementtarget.classList.toggle('in');
if(act === "show")
elementtarget.classList.add('in');
if(act === "hide")
elementtarget.classList.remove('in');
}
})
}
}
}
P.S. I tried using an arrow function but couldn't get the code to work properly.
Lets say I have a javascript object with the the following
var Settings = function () {
this.timelimit = 0;
this.locked = false;
this.expires = null;
this.age = null;
};
And then I set some get/set functions like:
Settings.prototype = {
getAllAges: function () {
return self.age;
},
getTimeLimit: function () {
return self.timelimit;
},
load: function() {
data_from_local_storage = LoadLocalStorage();
}
}
In data_from_local_storage I have JSON variables that match the above variables (timelimit, locked etc .. )
Issue is, the object var settings_ref = Settings() have all these 4 variables - but also have these 3 functions assigned in settings_ref - due to this OO behavior I need to write inside the load() function:
this.timelimit = data_from_local_storage.timelimit
this.age = data_from_local_storage.age
this.locked = data_from_local_storage.locked
Because if I'll write
this = data_from_local_storage it will destroy my object.
So how can I avoid writing all these variables one-by-one ?
w/o a for loop inside a function
in this example are just 4 but there are much much more and I cannot write it everywhere everytime
I'm looking for some .update() function like in Python or something ..
Any quick shortcut that someone know ?
You can use Object.assign() in ES2015:
load: function() {
Object.assign(this, LoadLocalStorage());
}
It's apparently not supported yet in IE, but there's a polyfill on the MDN page:
if (typeof Object.assign != 'function') {
(function () {
Object.assign = function (target) {
'use strict';
// We must check against these specific cases.
if (target === undefined || target === null) {
throw new TypeError('Cannot convert undefined or null to object');
}
var output = Object(target);
for (var index = 1; index < arguments.length; index++) {
var source = arguments[index];
if (source !== undefined && source !== null) {
for (var nextKey in source) {
if (source.hasOwnProperty(nextKey)) {
output[nextKey] = source[nextKey];
}
}
}
}
return output;
};
})();
}
(Personally I would use Object.defineProperty() to add the method, but that's verbatim from MDN.)
(edit though I guess if you don't have Object.assign() you may not have Object.defineProperty() either :)
If you store the data inside another object literal, it makes persisting things to localstorage and back a lot easier.. Here is an example..
//pretend local storage loader
function LoadLocalStorage() {
return {
timelimit: 100,
locked: true,
expires: new Date(),
age:40
}
}
var Settings = function () {
this.data = {
timelimit: 0,
locked: false,
expires: null,
age:null
}
};
Settings.prototype = {
getAllAges: function () {
return this.data.age;
},
getTimeLimit: function () {
return this.data.timelimit;
},
load: function() {
this.data = LoadLocalStorage();
}
}
var settings = new Settings;
console.log('Age before our load');
console.log(settings.getAllAges());
settings.load();
console.log('Age after our load');
console.log(settings.getAllAges());
I have this function check(e) that I'd like to be able to pass parameters from test() when I add it to the eventListener. Is this possible? Like say to get the mainlink variable to pass through the parameters. Is this even good to do?
I put the javascript below, I also have it on jsbin: http://jsbin.com/ujahe3/9/edit
function test() {
if (!document.getElementById('myid')) {
var mainlink = document.getElementById('mainlink');
var newElem = document.createElement('span');
mainlink.appendChild(newElem);
var linkElemAttrib = document.createAttribute('id');
linkElemAttrib.value = "myid";
newElem.setAttributeNode(linkElemAttrib);
var linkElem = document.createElement('a');
newElem.appendChild(linkElem);
var linkElemAttrib = document.createAttribute('href');
linkElemAttrib.value = "jsbin.com";
linkElem.setAttributeNode(linkElemAttrib);
var linkElemText = document.createTextNode('new click me');
linkElem.appendChild(linkElemText);
if (document.addEventListener) {
document.addEventListener('click', check/*(WOULD LIKE TO PASS PARAMETERS HERE)*/, false);
};
};
};
function check(e) {
if (document.getElementById('myid')) {
if (document.getElementById('myid').parentNode === document.getElementById('mainlink')) {
var target = (e && e.target) || (event && event.srcElement);
var obj = document.getElementById('mainlink');
if (target!= obj) {
obj.removeChild(obj.lastChild);
};
};
};
};
Wrap your event listener into a function:
document.addEventListener(
'click',
function(e,[params]){
check(e,[params]);
}
);
One solution would be to move the "check" function up inside your test() function. As an inner function, it would automatically be able to refer to variables in its outer scope. Like this:
function test() {
if (!document.getElementById('myid')) {
var mainlink = document.getElementById('mainlink');
var newElem = document.createElement('span');
mainlink.appendChild(newElem);
var linkElemAttrib = document.createAttribute('id');
linkElemAttrib.value = "myid";
newElem.setAttributeNode(linkElemAttrib);
var linkElem = document.createElement('a');
newElem.appendChild(linkElem);
var linkElemAttrib = document.createAttribute('href');
linkElemAttrib.value = "jsbin.com";
linkElem.setAttributeNode(linkElemAttrib);
var linkElemText = document.createTextNode('new click me');
linkElem.appendChild(linkElemText);
if (document.addEventListener) {
document.addEventListener('click', function(e) {
if (document.getElementById('myid')) {
if (document.getElementById('myid').parentNode === mainlink) {
var target = (e && e.target) || (event && event.srcElement);
if (target!= mainlink) {
mainlink.removeChild(mainlink.lastChild);
};
};
};
});
};
What I typically do in this situation is save arguments to the object (whenever it's convenient), and then retrieve them in the function, like this:
// Listener function receives e (the event object) by default.
function eventReceiver(e) {
var obj;
// Find object which triggered the event
e.srcElement ? obj = e.srcElement : obj = e.target;
// obj.someProperty has been set elsewhere, replacing a function parameter
alert(obj.someProperty);
}
This is cross browser, and allows you to pass objects and values through the properties of the event target.
I initially started with the this keyword, but that behaves differently cross-browser. In FF, it's the object that the event was triggered on. In IE, it's the event itself. Thus, the srcElement / target solution was born. I'm interested to see the other solutions though - have a +1.
I would like to trigger an events without duplicating code. So I decided to create a constructor function (class) and then a new object with a variable that connects to an event handler. Im just testing it but I cant get the if statement to trigger the alert() using this.link it works like this: if(el) but not like this: if(el === this.link)
var faqOne = document.getElementById("faqOne");
var hiddenOne = document.querySelector("p.faqOneHidden");
faqOne.addEventListener("click", function (e) {
showFaqOne.showClickedFaq(e);
}, false);
function DisplayQFaqs(link, faq) {
this.link = link;
this.faq = faq;
}
DisplayQFaqs.prototype.showClickedFaq = function (e) {
var el = e.target;
if (el === this.link) {
alert('hi');
}
};
var showFaqOne = new DisplayQFaqs(faqOne, hiddenOne);
I have the function below.
Everything works fine except for the Push, Pop and Remove method. These method should be called by the event-handler. This event is fired by the Google Maps API.
The problem is that when the event is fired, these method are not found. I have a "Push is not defined" error message.
I tried with this but that's not working.
How do I call the public method from the event handler?
function Track(mapContainer) {
var map = mapContainer;
var points = new Array();
var isEditMode = false;
var clickListener;
this.Push = function(point) { ... }
this.Pop = function() { ... }
this.Remove = function(point) { ... }
//Enable / disable the marker placements
this.PlaceWaypoint = function(isPlacing) {
if (isPlacing != true) {
if (clickListener != null) {
google.maps.event.removeListener(clickListener);
clickListener = null;
}
} else {
clickListener = map.AddEvent("click", function(event) {
if (!IsDoubleClick()) {
var point = map.PlaceMarker(new WayPoint(event.latLng))
point.RemoveListener(function() { Remove(point); });
Push(point);
} else {
Pop();
}
});
}
}
}
You've got a closure/binding problem. One convention that is frequently used it to assign a variable called self of that, which can later be used in place of this, thanks to the closure properties of JS.
function Track(mapContainer) {
var map = mapContainer,
points = new Array(),
isEditMode = false,
clickListener,
// Make a variable self that points to this, that can be used inside closures
// where the original context is lost
self = this;
this.Push = function(point) { ... }
this.Pop = function() { ... }
this.Remove = function(point) { ... }
//Enable / disable the marker placements
this.PlaceWaypoint =
function(isPlacing) {
if (isPlacing != true) {
if (clickListener != null) {
google.maps.event.removeListener(clickListener);
clickListener = null;
}
} else {
clickListener = map.AddEvent("click", function(event) {
if (!IsDoubleClick()) {
var point = map.PlaceMarker(new WayPoint(event.latLng))
point.RemoveListener(function() { Remove(point); });
// Use the closure reference self instead of this
self.Push(point);
} else {
// Use the closure reference self instead of this
self.Pop();
}
});
};
}
this always refers to the context of the current function, so if you use this in your event handler it refers to that function calls this, not the this in your Track function.
To create a closure that accesses the this of an outer scope, you need to assign that this to a new variable which can be accessed from the inner function:
var self = this;
this.PlaceWaypoint = function(isPlacing) {
// ...
self.Pop();
// ...
}
First of all Pop and Push is not global, second this in the inner scope has another meaning. So you can use closure and rename the "this" to variable of more global scope.
function Track(mapContainer) {
//....
var $this = this;
//Enable / disable the marker placements
this.PlaceWaypoint = function(isPlacing) {
if (isPlacing != true) {
if (clickListener != null) {
google.maps.event.removeListener(clickListener);
clickListener = null;
}
} else {
clickListener = map.AddEvent("click", function(event) {
if (!IsDoubleClick()) {
var point = map.PlaceMarker(new WayPoint(event.latLng))
point.RemoveListener(function() { $this.Remove(point); });
$this.Push(point);
} else {
$this.Pop();
}
});
}
}
}