I am using dexie.js, which is an indexDB wrapper. Anywhoo, I have an array that is called from the user's local storage, and my function is supposed to iterate through every list item in the DB and show it. However, upon clicking on my Butane it only shows the most recent input of name.
Note: You can see the entire database by adding a few values in and checking your local storage.
My JsFiddle:
https://jsfiddle.net/enzp3zws/1/
my html:
<ul id="mane"></ul>
my js:
var db = new Dexie("TestDatabase");
db.version(1).stores({
friends: '++id, name, age'
});
var collection = db.friends;
var placement = document.getElementById('rainman');
var jacement = document.getElementById('rainboy');
var stacement = document.getElementById('mane');
var listed = document.createElement('li');
function addrain(){
collection.each(function(friend){
var element = [friend.name];
for (var i = 0; i < element.length; i++){
listed.textContent = element[i];
document.getElementById('mane').appendChild(listed);
//alert(element); <-- this call alerts all names in database.
}
});
}
Please excuse the randomness of some of these variable names. I don't know what sleep is anymore.
You need to create a new 'li' element each time:
//Remove var listed = ... line in header, then:
function addrain(){
collection.each(function(friend){
var element = [friend.name];
for (var i = 0; i < element.length; i++){
var listed = document.createElement('li');
listed.textContent = element[i];
document.getElementById('mane').appendChild(listed);
}
//alert(element); <-- this call alerts all names in database.
});
}
The reason your code did not work before is that you only created one li element, and repeatedly changed its text and re-inserted it at different locations.
Related
I am building a Todo-List Project and i am stuck at looping through my newly created list items.
This is what i am doing:
Created an array.
Made li items for array's each element through looping so that array appears in a list manner.
And then looping through newly created li section to addEventListener on each of li's ( But this one is not working).
var arrList = ["play","learn","walk"];
var list = document.querySelectorAll("li");
var done = false;
//printing array in list manner
for(let i = 0; i < arrList.length; i++){
let el = document.createElement("li")
el.textContent = arrList[i];
document.querySelector("ul").appendChild(el);
}
//looping through each li's to apply if else statement
for(let i = 0; i < list.length; i++){
list[i].addEventListener("click",function(){
if(!done){
this.style.textDecoration = "line-through";
done = true;
}else{
this.style.textDecoration = "none";
done = false;
}
})
}
You're code is mostly correct, however there are a few issues that need to be addressed. First, consider replacing your for loop with iteration based on forEach() as shown below. Using forEach() in this way allows you to leverage "closure" which in this case will greatly simplify your code. For instance, you can use the closure feature to store the done state of each item in your list, rather than storing that state explicitly in an array.
The other issue I noticed was var list = document.querySelectorAll("li"); queries the document for li elements before any are added to your document - later in your script it seems you're iterating that empty query result and expecting it to contain the added li elements.
Here's a working snippet - hope this helps!
var arrList = ["play", "learn", "walk"];
// Iterate the list via forEach
arrList.forEach(function(arrItem) {
// We're now in a new "closure" for this list item
// so we can define some state like "done" that will
// be used exclusively for this list item
var done = false;
// Create li element for this list item as before
var el = document.createElement("li")
el.textContent = arrItem;
// Configure click event
el.addEventListener("click", function() {
// Notice we're able to use the done variable
// in this closure for this list item? The key
// thing to understand is that each list item
// will have it's own unique "done" variable
if (!done) {
el.style.textDecoration = "line-through";
done = true;
} else {
el.style.textDecoration = "none";
done = false;
}
})
document.querySelector("ul").appendChild(el);
});
<ul></ul>
It seems like you only have one done variable that is shared for every item on the todo list. Therefore if you click one of the items all of the items will be crossed out. You will need a boolean variable for every item in your to do list.
Add this line just above the second for loop and remove from the top.
var list = document.querySelectorAll("li");
You are assigning list the values even before they are created.
from the source code I see that the list li item is initialized before new li item been created,
it will cause the list li item not contains the new one,
due to that addEventListener will not working for the new item.
to fix this, just need move init list li item code after creation part :
var arrList = ["play","learn","walk"];
var done = false;
//printing array in list manner
for(let i = 0; i < arrList.length; i++){
let el = document.createElement("li")
el.textContent = arrList[i];
document.querySelector("ul").appendChild(el);
}
var list = document.querySelectorAll("li");
//looping through each li's to apply if else statement
for(let i = 0; i < list.length; i++){
list[i].addEventListener("click",function(){
if(!done){
this.style.textDecoration = "line-through";
done = true;
}else{
this.style.textDecoration = "none";
done = false;
}
})
}
Please, be simple...
var
arrList = ["play","learn","walk"],
UL_arrList = document.querySelector("ul")
;
arrList.forEach (arrItem => {
let el = document.createElement("li");
el.textContent = arrItem;
UL_arrList.appendChild(el);
el.onclick = function(e){
let deco = this.style.textDecoration || 'none';
this.style.textDecoration = (deco==='none') ? 'line-through': 'none';
}
});
<ul></ul>
I can make variables one by one like this:
var bookName = document.getElementById('bookName').value,
author = document.getElementById('author').value,
translator = document.getElementById('translator').value,
pageCount = document.getElementById('pageCount').value,
publisher = document.getElementById('publisher').value,
isbn = document.getElementById('isbn').value,
printingYear = document.getElementById('printingYear').value;
But it's so hard to write and it doesn't fit with the DRY rule. So I changed the code to this:
function variableMaker(argument) {
var tags = document.getElementsByTagName(argument);
for (var i = 0; i < tags.length; i++) {
var tags[i].name = tags[i].value;
}
}
variableMaker(input);
But I can't understand if it is the true way or if it is working? How do I check if it's true or not?
In this code, I tried to get the computer find all the input tags and make variables with their name property and assign it to its values for each of them.
If I understand correctly then you want to gather data from all <input> elements. If so, then you need to call it like this:
variableMaker('input'); // use quotes!
Still even then your function does not return anything, it just ends.
You'd also better create your own object for the return collection, instead of adding values to an existing object.
Here is a working solution:
function variableMaker(tagName) {
var elements = document.getElementsByTagName(tagName);
var items = {};
for (var i = 0; i < elements.length; i++) {
var elem = elements[i];
items[elem.id] = elem.value; // Use id as key, each points to the corresponding value.
}
return items;
}
var values = variableMaker('input');
console.log(values); // show the entire return object
console.log(values.author); // access individual items from the return object
console.log(values.isbn);
<input type="text" id="author" value="Dahl">
<input type="text" id="isbn" value="1234">
.
I am pretty new to the 'game' and was wondering if it's possible to order newly added data (through a form and inputs) to the Firebase numerically so each new data entry gets the ID (number of the last added data +1).
To make it more clear, underneath you can find a screenshot of how data is currently being added right now. The datapoint 0-7 are existing (JSON imported data) and the ones with the randomly created ID belong to new entries. I would like to have the entries to comply to the numbering inside of my Firebase, because otherwise my D3 bar chart won't be visualised.
var firebaseData = new Firebase("https://assignment5.firebaseio.com");
function funct1(evt)
{
var gameName = $('#nameInput').val();
var medalCount = $('#medalsInput').val();
var bool = $('#boolInput').is(':checked');
firebaseData.push().set({games: gameName, medals: medalCount, summergames: bool});
evt.preventDefault();
}
var submit = document.getElementsByTagName('button')[0];
submit.onclick = funct1;
UPDATE:
function funct1(evt)
{
var gameName = $('#nameInput').val();
var medalCount = $('#medalsInput').val();
var bool = $('#boolInput').is(':checked');
for (var i = 0; i < 10; i++)
{
firebaseData.child('7' + i).set({games: gameName, medals: medalCount, summergames: bool}(i)); };
Problem:
There are two ways to generate ids for your document nodes.
Calling .push() on your reference will generate that unique id.
Calling .set() on your reference will allow you to use your own
id.
Right now you're using .push().set({}), so push will generate an new id and the set will simply set the data.
// These two methods are equivalent
listRef.push().set({user_id: 'wilma', text: 'Hello'});
listRef.push({user_id: 'wilma', text: 'Hello'});
Using .set() without .push() will allow you to control your own id.
Using .push():
When managing lists of data in Firebase, it's important to use unique generated IDs since the data is updating in real time. If integer ids are being used data can be easily overwritten.
Just because you have an unique id, doesn't mean you can't query through your data by your ids. You can loop through a parent reference and get all of the child references as well.
var listRef = new Firebase('https://YOUR-FIREBASE.firebaseio.com/items');
// constructor for item
function Item(id) {
this.id = id;
};
// add the items to firebase
for (var i = 0; i < 10; i++) {
listRef.push(new Item(i));
};
// This will generate the following structure
// - items
// - LGAJlkejagae
// - id: 0
// now we can loop through all of the items
listRef.once('value', function (snapshot) {
snapshot.forEach(function (childSnapshot) {
var name = childSnapshot.name();
var childData = childSnapshot.val();
console.log(name); // unique id
console.log(childData); // actual data
console.log(childData.id); // this is the id you're looking for
});
});
Within the childData variable you can access your data such as the id you want.
Using .set()
If you want to manage your own ids you can use set, but you need to change the child reference as you add items.
for (var i = 0; i < 10; i++) {
// Now this will create an item with the id number
// ex: https://YOUR-FIREBASE.firebaseio.com/items/1
listRef.child('/' + i).set(new Item(i));
};
// The above loop with create the following structure.
// - items
// - 0
// - id: 0
To get the data you can use the same method above to loop through all of the child items in the node.
So which one to use?
Use .push() when you don't want your data to be easily overwritten.
Use .set() when your id is really, really important to you and you don't care about your data being easily overwritten.
EDIT
The problem you're having is that you need to know the total amount of items in the list. This feature is not implemented in Firebase so you'll need to load the data and grab the number of items. I'd recommend doing this when the page loads and caching that count if you really desire to maintain that id structure. This will cause performance issues.
However, if you know what you need to index off of, or don't care to overwrite your index I wouldn't load the data from firebase.
In your case your code would look something like this:
// this variable will store all your data, try to not put it in global scope
var firebaseData = new Firebase('your-firebase-url/data');
var allData = null;
// if you don't need to load the data then just use this variable to increment
var allDataCount = 0;
// be wary since this is an async call, it may not be available for your
// function below. Look into using a deferred instead.
firebaseData.once('value', function(snapshot) {
allData = snapshot.val();
allDataCount = snapshot.numChildren(); // this is the index to increment off of
});
// assuming this is some click event that adds the data it should
function funct1(evt) {
var gameName = $('#nameInput').val();
var medalCount = $('#medalsInput').val();
var bool = $('#boolInput').is(':checked');
firebaseData.child('/' + allDataCount).set({
games: gameName,
medals: medalCount,
summergames: bool
});
allDataCount += 1; // increment since we still don't have the reference
};
For more information about managing lists in Firebase, there's a good article in the Firebase API Docs. https://www.firebase.com/docs/managing-lists.html
Getting a bit stuck on this, have a got a list of items from an json file. The problem is I want to separate the file in ul li of ten. rather than having a long list of li. I want to separate them into to bootstrap columns of 3 for example col-lg-4, needs to be in javascript and not in query.
This is what I've got so far:
function buildCountryList(countryData) {
var countryName = null;
var countryURL = null;
var countryListContainer = document.getElementById('countryList');
var countryList = document.createElement("ul");
var countryListItem = document.createElement("li");
var countryLink = document.createElement("a");
countryLoaded = true;
for (var i = 0; i < countryData.countryList.length; i++) {
countryName = countryData.countryList[i].country;
countryURL = countryData.countryList[i].url;
countryLink.href = countryURL;
countryLink.innerHTML = countryName;
// countryListItem.appendChild(countryLink);
// countryList.appendChild(countryListItem);
// countryListContainer.appendChild(countryList);
}
}
Notice you need create a new <li> element inside the loop by var. Other wise it's just going to be overwrite each other.
Here is a working demo of what I believe you wanted : http://jsfiddle.net/kP5zX/1/
basicly just fix the error I mentioned and use .className to add bootstrap class names.
okay i have come across a simple javascript code that will search all the hyperlinks in a page which works briliantly fast. the only problem is that the browser freezes when it tries to remake these links in a div, no error just as soon as i push the button the browser refuses to load. as you can see it gets the input from a form then searches every hyperlink for these terms then is supposed to populate a div with links but it doesn't. the code is as follows.
function search0(){
var lists = document.getElementsByTagName("a");
for (var i = 0; i < lists.length; i++) {
var output = lists[i];
var team1 = document.getElementById("search1").value;
var matchPos1 = output.innerHTML.search(team1);
if(matchPos1 != -1){
var team2 = document.getElementById("search2").value;
var matchPos2 = output.innerHTML.search(team2);
if(matchPos2 != -1){
var elem1 = document.createElement("a")
var styleattr=document.createAttribute("href");
styleattr.nodeValue=output;
elem1.setAttributeNode(styleattr);
var text1 = document.createTextNode(output.innerhtml);
elem1.appendChild(text1);
var parentdiv = document.getElementById("frame2");
parentdiv.appendChild(elem1);
}
}
}
}
You are creating an infinite loop.
The nodeList you create with document.getElementsByTagName("a") is live i.e. if you add a link to the page it will appear in this list automatically! Yes, that's right, even without requerying. Here's a reference doc.
You are adding links to the nodeList which are then matched and added to the end on the nodeList which are then matched and so on and so on
To do what you want to do you should create an initial array of links like this.
//creates a real js array from a nodelist
var list = Array.prototype.slice.call( document.getElementsByTagName("a"), 0 );
Here is an explanation of Array.prototype.slice.call
Also change case-sensitive mistake:
var text1 = document.createTextNode(output.innerhtml);
To
var text1 = document.createTextNode(output.innerHTML);