folks! Today I created this script that has the following functionality:
add new items to array
list all items from the array
remove an item from the array
There are two functions:
addToFood() - adds the value of input to the array and updates
innerHTML of div
removeRecord(i) - remove a record from the array and updates
innerHTML of div
The code includes 3 for loops and you can see it at - http://jsfiddle.net/menian/3b4qp/1/
My Master told me that those 3 for loops make the solution way to heavy. Is there a better way to do the same thing? Is it better to decrease the loops and try to use splice? Thanks in advance.
HTML
<!-- we add to our foodList from the value of the following input -->
<input type="text" value="food" id="addFood" />
<!-- we call addToFood(); through the following button -->
<input type="submit" value="Add more to food" onClick="addToFood();">
<!-- The list of food is displayed in the following div -->
<div id="foods"></div>
JavaScript
var foodList = [];
function addToFood () {
var addFood = document.getElementById('addFood').value;
foodList.push(addFood);
for (i = 0; i < foodList.length; i++) {
var newFood = "<a href='#' onClick='removeRecord(" + i + ");'>X</a> " + foodList[i] + " <br>";
};
document.getElementById('foods').innerHTML += newFood;
}
function removeRecord (i) {
// define variable j with equal to the number we got from removeRecord
var j = i;
// define and create a new temporary array
var tempList = [];
// empty newFood
// at the end of the function we "refill" it with the new content
var newFood = "";
for (var i = 0; i < foodList.length; i++) {
if(i != j) {
// we add all records except the one == to j to the new array
// the record eual to j is the one we've clicked on X to remove
tempList.push(foodList[i]);
}
};
// make redefine foodList by making it equal to the tempList array
// it should be smaller with one record
foodList = tempList;
// re-display the records from foodList the same way we did it in addToFood()
for (var i = 0; i < foodList.length; i++) {
newFood += "<a href='#' onClick='removeRecord(" + i + ");'>X</a> " + foodList[i] + " <br>";
};
document.getElementById('foods').innerHTML = newFood;
}
You should use array.splice(position,nbItems)
function removeRecord (i) {
foodList.splice(i, 1); // remove element at position i
var newFood = "";
for (var i = 0; i < foodList.length; i++) {
newFood += "<a href='#' onClick='removeRecord(" + i + ");'>X</a> "
+ foodList[i] + " <br>";
};
document.getElementById('foods').innerHTML = newFood;
}
http://jsfiddle.net/3b4qp/5/
Now using JQuery:
$(function(){
$(document).on('click','input[type=submit]',function(){
$('#foods')
.append('<div>X '
+ $('#addFood').val() + '</div>');
});
$(document).on('click','.item',function(){
$(this).parent().remove();
});
});
http://jsfiddle.net/jfWa3/
Your problem isn't the arrays, your problem is this code:
node.innerHTML += newFood;
This code is very, very, very slow. It will traverse all exising DOM nodes, create strings from them, join those strings into one long string, append a new string, parse the result to a new tree of DOM nodes.
I suggest to use a framework like jQuery which has methods to append HTML fragments to existing DOM nodes:
var parent = $('#foods');
...
for (var i = 0; i < foodList.length; i++) {
parent.append( "<a href='#' onClick='removeReco..." );
That will parse the HTML fragments only once.
If you really must do it manually, then collect all the HTML in a local string variable (as suggested by JohnJohnGa in his answer) and then assign innerHTML once.
Here's some tips to, at least, make your code more portable (dunno if it will be better performance wise, but should be, since DOM Manipulation is less expensive)
Tips
First separate your event handle from the HTML
Pass the "new food" as a function paramater
Tie the array elements to the DOM using the ID
Instead of rerendering everything when something changes (using innerHTML in the list), just change the relevant bit
Benefits:
You actually only loop once (when removing elements from the array).
You don't re-render the list everytime something changes, just the element clicked
Added bonus: It's more portable.
Should be faster
Example code:
FIDDLE
HTML
<div id="eventBinder">
<!-- we add to our foodList from the value of the following input -->
<input id="addFood" type="text" value="food" />
<!-- we call addToFood(); through the following button -->
<button id="addFoodBtn" value="Add more to food">Add Food</button>
<!-- The list of food is displayed in the following div
-->
<div id="foods"></div>
</div>
JS
// FoodList Class
var FoodList = function (selectorID) {
return {
foodArray: [],
listEl: document.getElementById(selectorID),
idCnt: 0,
add: function (newFood) {
var id = 'myfood-' + this.idCnt;
this.foodArray.push({
id: id,
food: newFood
});
var foodDom = document.createElement('div'),
foodText = document.createTextNode(newFood);
foodDom.setAttribute('id', id);
foodDom.setAttribute('class', 'aFood');
foodDom.appendChild(foodText);
this.listEl.appendChild(foodDom);
++this.idCnt;
},
remove: function (foodID) {
for (var f in this.foodArray) {
if (this.foodArray[f].id === foodID) {
delete this.foodArray[f];
var delFood = document.getElementById(foodID);
this.listEl.removeChild(delFood);
}
}
}
};
};
//Actual app
window.myFoodList = new FoodList('foods');
document.getElementById('eventBinder').addEventListener('click', function (e) {
if (e.target.id === 'addFoodBtn') {
var food = document.getElementById('addFood').value;
window.myFoodList.add(food);
} else if (e.target.className === 'aFood') {
window.myFoodList.remove(e.target.id);
}
}, false);
Here is another sugestion:
function remove(arr, index) {
if (index >= arr.lenght) { return undefined; }
if (index == 0) {
arr.shift();
return arr;
}
if (index == arr.length - 1) {
arr.pop();
return arr;
}
var newarray = arr.splice(0, index);
return newarray.concat(arr.splice(1,arr.length))
}
Related
I'm writing the first item of an array to the screen, and would like to create Next/Previous buttons for array, but I can't get it to work. I have tried several methods, but I can't find suitable solution.
Can anyone help?
This is the last one I have tried:
var data = [
{"subject":"starcraft2",
"date":"08.31",
"dDay":"mon",
"content1":"STARCRAFT2",
"content2":"season2",
"playerA":"Ju",
"playerB":"Lee",
"emblemA":"Terran",
"emblemB":"Zerg",
"result":"end"},
{"subject":"starcraft2",
"date":"08.29",
"dDay":"wed",
"content1":"STARCRAFT2",
"content2":"season2",
"playerA":"kim",
"playerB":"joo",
"emblemA":"Terran",
"emblemB":"Protoss",
"result":"end"},
];
function prevAction() {
// function (e) { // the e here is the event itself
alert("Prev Click!");
// document.getElementById('subject').textContent = prevItem();
// document.getElementById('date').textContent = prevItem();
for (var i = 0; i<data.length; i++)
for (var j=0; j<data[i]; j++)
while(j === 0)
{
j == j++;
console.log(j);
}
console.log(data[j].date + ', ');
document.getElementById('date').textContent = data[j].date;
// document.getElementById('subject').textContent = j[0];
}
Here's the jist of how you'd accomplish this in pure Javascript:
getNextItem() {
var index = document.getElementById("index").value;
//add guards here to prevent array overflow/underflow
if (data.length < index - 1) {
index.value++;
}
document.getElementById("DOM_ELEMENT_TO_ATTACH_DATA").innerHTML = data[index];
}
getPreviousItem() {
var index = document.getElementById("index").value;
//add guards here to prevent array overflow/underflow
if (index > 0) {
index.value--;
}
document.getElementById("DOM_ELEMENT_TO_ATTACH_DATA").innerHTML = data[index];
}
<input id="index" type="hidden" name="index" value="0">
<button type="button" onclick="getNextItem()">Next Item</button>
<button type="button" onclick="getPreviousItem()">Previous Item</button>
Note that this will just attach the pure json data to a DOM element, it won't do anything fancy with it.
Furthermore, if you want to do anything more complex, I'd strongly recommend you look into using a library like jQuery or Angular as it's going to make your life a whole lot easier in the long run.
Am struggling hard to bind an array object with list of span values using watcher in Angularjs.
It is partially working, when i input span elements, an array automatically gets created for each span and when I remove any span element -> respective row from the existing array gets deleted and all the other rows gets realigned correctly(without disturbing the value and name).
The problem is when I remove a span element and reenter it using my input text, it is not getting added to my array. So, after removing one span element, and enter any new element - these new values are not getting appended to my array.
DemoCode fiddle link
What am I missing in my code?
How can I get reinserted spans to be appended to the existing array object without disturbing the values of leftover rows (name and values of array)?
Please note that values will get changed any time as per a chart.
This is the code am using:
<script>
function rdCtrl($scope) {
$scope.dataset_v1 = {};
$scope.dataset_wc = {};
$scope.$watch('dataset_wc', function (newVal) {
//alert('columns changed :: ' + JSON.stringify($scope.dataset_wc, null, 2));
$('#status').html(JSON.stringify($scope.dataset_wc));
}, true);
$(function () {
$('#tags input').on('focusout', function () {
var txt = this.value.replace(/[^a-zA-Z0-9\+\-\.\#]/g, ''); // allowed characters
if (txt) {
//alert(txt);
$(this).before('<span class="tag">' + txt.toLowerCase() + '</span>');
var div = $("#tags");
var spans = div.find("span");
spans.each(function (i, elem) { // loop over each spans
$scope.dataset_v1["d" + i] = { // add the key for each object results in "d0, d1..n"
id: i, // gives the id as "0,1,2.....n"
name: $(elem).text(), // push the text of the span in the loop
value: 3
}
});
$("#assign").click();
}
this.value = "";
}).on('keyup', function (e) {
// if: comma,enter (delimit more keyCodes with | pipe)
if (/(188|13)/.test(e.which)) $(this).focusout();
if ($('#tags span').length == 7) {
document.getElementById('inptags').style.display = 'none';
}
});
$('#tags').on('click', '.tag', function () {
var tagrm = this.innerHTML;
sk1 = $scope.dataset_wc;
removeparent(sk1);
filter($scope.dataset_v1, tagrm, 0);
$(this).remove();
document.getElementById('inptags').style.display = 'block';
$("#assign").click();
});
});
$scope.assign = function () {
$scope.dataset_wc = $scope.dataset_v1;
};
function filter(arr, m, i) {
if (i < arr.length) {
if (arr[i].name === m) {
arr.splice(i, 1);
arr.forEach(function (val, index) {
val.id = index
});
return arr
} else {
return filter(arr, m, i + 1)
}
} else {
return m + " not found in array"
}
}
function removeparent(d1)
{
dataset = d1;
d_sk = [];
Object.keys(dataset).forEach(function (key) {
// Get the value from the object
var value = dataset[key].value;
d_sk.push(dataset[key]);
});
$scope.dataset_v1 = d_sk;
}
}
</script>
Am giving another try, checking my luck on SO... I tried using another object to track the data while appending, but found difficult.
You should be using the scope as a way to bridge the full array and the tags. use ng-repeat to show the tags, and use the input model to push it into the main array that's showing the tags. I got it started for you here: http://jsfiddle.net/d5ah88mh/9/
function rdCtrl($scope){
$scope.dataset = [];
$scope.inputVal = "";
$scope.removeData = function(index){
$scope.dataset.splice(index, 1);
redoIndexes($scope.dataset);
}
$scope.addToData = function(){
$scope.dataset.push(
{"id": $scope.dataset.length+1,
"name": $scope.inputVal,
"value": 3}
);
$scope.inputVal = "";
redoIndexes($scope.dataset);
}
function redoIndexes(dataset){
for(i=0; i<dataset.length; i++){
$scope.dataset[i].id = i;
}
}
}
<div ng-app>
<div ng-controller="rdCtrl">
<div id="tags" style="border:none;width:370px;margin-left:300px;">
<span class="tag" style="padding:10px;background-color:#808080;margin-left:10px;margin-right:10px;" ng-repeat="data in dataset" id="4" ng-click="removeData($index)">{{data.name}}</span>
<div>
<input type="text" style="margin-left:-5px;" id="inptags" value="" placeholder="Add ur 5 main categories (enter ,)" ng-model="inputVal" />
<button type="submit" ng-click="addToData()">Submit</button>
<img src="../../../static/app/img/accept.png" ng-click="assign()" id="assign" style="cursor:pointer;display:none" />
</div>
</div>
<div id="status" style="margin-top:100px;"></div>
</div>
</div>
I have a list with about 10 000 customers on a web page and need to be able to search within this list for matching input. It works with some delay and I'm looking for the ways how to improve performance. Here is simplified example of HTML and JavaScript I use:
<input id="filter" type="text" />
<input id="search" type="button" value="Search" />
<div id="customers">
<div class='customer-wrapper'>
<div class='customer-info'>
...
</div>
</div>
...
</div>
<script type="text/javascript">
$(document).ready(function() {
$("#search").on("click", function() {
var filter = $("#filter").val().trim().toLowerCase();
FilterCustomers(filter);
});
});
function FilterCustomers(filter) {
if (filter == "") {
$(".customer-wrapper").show();
return;
}
$(".customer-info").each(function() {
if ($(this).html().toLowerCase().indexOf(filter) >= 0) {
$(this).parent().show();
} else {
$(this).parent().hide();
}
});
}
</script>
The problem is that when I click on Search button, there is a quite long delay until I get list with matched results. Are there some better ways to filter list?
1) DOM manipulation is usually slow, especially when you're appending new elements. Put all your html into a variable and append it, that results in one DOM operation and is much faster than do it for each element
function LoadCustomers() {
var count = 10000;
var customerHtml = "";
for (var i = 0; i < count; i++) {
var name = GetRandomName() + " " + GetRandomName();
customerHtml += "<div class='customer-info'>" + name + "</div>";
}
$("#customers").append(customerHtml);
}
2) jQuery.each() is slow, use for loop instead
function FilterCustomers(filter) {
var customers = $('.customer-info').get();
var length = customers.length;
var customer = null;
var i = 0;
var applyFilter = false;
if (filter.length > 0) {
applyFilter = true;
}
for (i; i < length; i++) {
customer = customers[i];
if (applyFilter && customer.innerHTML.toLowerCase().indexOf(filter) < 0) {
$(customer).addClass('hidden');
} else {
$(customer).removeClass('hidden');
}
}
}
Example: http://jsfiddle.net/29ubpjgk/
Thanks to all your answers and comments, I've come at least to solution with satisfied results of performance. I've cleaned up redundant wrappers and made grouped showing/hiding of elements in a list instead of doing separately for each element. Here is how filtering looks now:
function FilterCustomers(filter) {
if (filter == "") {
$(".customer-info").show();
} else {
$(".customer-info").hide();
$(".customer-info").removeClass("visible");
$(".customer-info").each(function() {
if ($(this).html().toLowerCase().indexOf(filter) >= 0) {
$(this).addClass("visible");
}
});
$(".customer-info.visible").show();
}
}
And an test example http://jsfiddle.net/vtds899r/
The problem is that you are iterating the records, and having 10000 it can be very slow, so my suggestion is to change slightly the structure, so you won't have to iterate:
Define all the css features of the list on customer-wrapper
class and make it the parent div of all the list elements.
When your ajax request add an element, create a variable containing the name replacing spaces for underscores, let's call it underscore_name.
Add the name to the list as:
var customerHtml = "<div id='"+underscore_name+'>" + name + "</div>";
Each element of the list will have an unique id that will be "almost" the same as the name, and all the elements of the list will be on the same level under customer-wrapper class.
For the search you can take the user input replace spaces for underscores and put in in a variable, for example searchable_id, and using Jquery:
$('#'+searchable_id).siblings().hide();
siblings will hide the other elements on the same level as searchable_id.
The only problem that it could have is if there is a case of two or more repeated names, because it will try to create two or more divs with the same id.
You can check a simple implementation on http://jsfiddle.net/mqpsppxm/
(according webshop)
I want to add an function remove, where I remove the whole entry inserted using ajax & jquery, but it is not working as I want to.
Using the following code:
$('#div').on('click', '.orderd', function() {
$(this).remove();
});
function UpdateTotal() {
ToAddHTML = '<h1>Shopping cart</h1>';
Totalprice = 0;
for (var i = 0; i < orders.length ; i++) {
var zoekresultaat = SubMenuItems.filter(function(v) {
return v.submenu_id === orders[i];
})[0];
Totalprice += parseFloat(searched.price);
ToAddHTML += '';
}
ToAddHTML += ''
$("#totalen").html(ToAddHTML);
}
This works, but when I console.log the array "orderd items", it still repeats the orderd items.
So when I click on a different item, the "just-deleted" order is popping up again.
It's kind of hard to explain my current problem, but I hope i've informed enough! For any questions, please ask! ill update my question!
You should remove the ordered id from your array, and recalculate your "basket" when an item is removed.
// =======================================================================
// ! Functie maken die de totalen-lijst bijwerkt
// =======================================================================
function WerkTotalenBij() {
ToeTeVoegenHTML = '<h1>Winkelmandje</h1>';
Totaalprijs = 0;
for (var i = 0; i < Bestellingen.length ; i++) {
var zoekresultaat = SubMenuItems.filter(function(v) {
return v.submenu_id === Bestellingen[i];
})[0];
Totaalprijs += parseFloat(zoekresultaat.price);
// here I put a "data-itemid" attribute to keep a raw reference to the item id
// this ID can be retrieved in the remove handler
ToeTeVoegenHTML += '<div class=besteld id=nummer'+Bestellingen[i]+' data-itemid="'+Bestellingen[i]+'">'+'€'+zoekresultaat.price+' '+zoekresultaat.title+'</br>(verwijder)</div><hr>';
}
ToeTeVoegenHTML += '<br/>Totale prijs per persoon :<br/> € '+Totaalprijs+'<br/>Minimaal 10 personen<br/> Aantal personen:<input type=text width="10px" /><input type="button" value="Ik ben klaar!">';
$("#totalen").html(ToeTeVoegenHTML);
}
$('#totalen').on('click', '.besteld', function() {
var itemID = $(this).data("itemid");
// remove the item ID from the array
var index = Bestellingen.indexOf(itemID);
if (index > -1) {
Bestellingen.splice(index, 1);
}
$(this).remove();
// recalculate orders
WerkTotalenBij();
});
But anyway, this is the typical work where you should rather use for example knockout.js libaray, where you can bind your DOM elements directly to your data, and it's enought to manipulate with your data, the GUI will automatically reflect to the changes. Believe me, it's worth to learn it, you won't regret.
So I have set up two javascript arrays to pull information from some php. One array gets the name of the category to be clicked on, while the other array stores the class and id tag for the category. The class and id tags are the same other than there css type, but the array needs to output them into document elements and then, when clicked, affect the relevant areas of the document. I also need to remove duplicates from the arrays, which doesn't seem to work under my current code:
<script type="text/javascript">
var BookSeries = [];
var BookClass = [];
var i=0;
</script>
then variables for the array are pulled from php and output this way:
<script type="text/javascript">
var uniqueSeries = BookSeries.filter(function(elem, pos) {
return BookSeries.indexOf(elem) == pos;
});
var uniqueClass = BookClass.filter(function(elem, pos) {
return BookClass.indexOf(elem) == pos;
});
while (uniqueSeries[i]) {
document.write( "<span id='"+uniqueClass[i]+"'>"+uniqueSeries[i]+"</span>" );
i++;
}
for(var i = 0; i < uniqueClass.length; i++) {
$np("#"+uniqueClass[i]).click(function(){
$np(".postitem").fadeOut(200);
$np("."+uniqueClass[i]).fadeIn(200);
});
}
</script>
You are using jquery so you can do the following for appending the elements to the DOM:
var htmlString = "";
for (var i = 0; i < uniqueSeries.length; i++) {
htmlString += "<span id='"+uniqueClass[i]+"'>"+uniqueSeries[i]+"</span>";
}
$("#myContainer").html(htmlString);
Not sure what is $np so I'll assume you meant jquery's $.
for(var i = 0; i < uniqueClass.length; i++) {
var uClass = uniqueClass[i];
$("#" + uClass).click(function(){
$(".postitem").fadeOut(200);
$("." + uClass).fadeIn(200);
});
}
Edit:
"#myContainer" refers to the id of the dom element you want to append the html to. if you just want to append it to document you can do:
$(document).appendTo(htmlString);
Also see I updated the code above to reflect your comments about the uniqueClass array.