Im updating many fields using ajax. My server is getting a row from the database then I am JSON encoding the row and sending this as my xmlhttp.responseText.
The response text is of the form
{"JobCardNum":5063,"IssueTo":"MachineShop","Priority":"High" ...lots of data}
In the browser I then JSON parse the response text and then begin the long process of updating the values like so:
var obj = JSON.parse(info);
document.getElementById("JobCardNum").value = obj.JobCardNum;
document.getElementById("IssueTo").value = obj.IssueTo;
document.getElementById("MachineShop").value = obj.MachineShop;
....... lots of similar statements
As the element id matches the column names I though there might be a way to loop through my JavaScript object and set all my values. Any Ideas?
This code should iterate over your json object and update the values.
for (var key in p) {
if (p.hasOwnProperty(key)) {
var el = document.getElementById(key);
if(el) el.value = p[key];
}
}
The solution using Object.keys and Array.forEach functions:
var obj = JSON.parse(info);
Object.keys(obj).forEach(function(id){
var el = document.getElementById(id);
if (el) el.value = obj[id];
});
Related
I have this stored in the session:
What I'm looking to do is assign each object in the JSON as a variable so I can add them to the DOM appropriately.
This works but prints everything out:
if (sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9') != null) {
$(sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9')).appendTo('.div');
}
What I'd like is something like this, but it doesn't work:
var div1 = $(JSON.parse(sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9', 'a.cart-contents')));
var div2 = $(JSON.parse(sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9', 'a.footer-cart-contents')));
var div3 = $(JSON.parse(sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9', 'div.widget_shopping_cart_content')));
Any help would be greatly appreciated. Thank you!
Getting the same value from the storage several times is not a good idea. In addition, you need better names for your variables.
var json = sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9');
if (json) {
var data = JSON.parse(json);
if (data) {
var cart_link = $(data['a.cart-contents']),
footer_link = $(data['a.footer-cart-contents']),
widget_div = $(data['div.widget_shopping_cart_content']);
}
}
So it appears you have set selectors as keys of the object so you could iterate those keys to get each selector.
The propose of those selector keys is not 100% clear. I am assuming that those selectors are the elements you want to insert the html strings into and that $() means you are using jQuery
if (sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9') != null) {
var data = JSON.parse(sessionStorage.getItem('wc_fragments_aaf6a2e5b971cb51d59e8f3eae9b34c9');
$.each(data, function(selector, htmlString){
$(selector).append(htmlString)
});
}
I have an object declared, and I have an html form with some matching fields.
All fields in the form are in the object, but the object also has a couple of additional variables and functions.
I'd like to fill the object with the data entered in the form, what I'm trying right now overwrites the declared object, and so doesn't have the functions nor the other variables.
The object :
var Container = {
nodes: [],
Contains: function (Node) {
for (var i = 0; i < this.nodes.length; i++) {
if (this.nodes[i].nodeID === Node.nodeID)
return (i);
}
return (-1);
}
How I fill it from the form :
const handleContainerForm = event => {
event.preventDefault();
ContainerFormToJSON(form.elements);
var i = JSONData.Contains(Container);
if (i === -1)
JSONData.containers.push(Container);
else
JSONData.container[i] = Container;
output = JSON.stringify(JSONData, null, " ");
displayContents(output);
};
The form has ID, Title, Folder, Image and Description as fields, so this last Container object doesn't have the Contains() function nor the nodes[] array.
How do I end up with a complete, filled version of the object I have declared ?
In ContainerFormToJSON function, before the statement
return Container
define:
//container.nodes and container.contains
You are right, JavaScript is very different from C#, especially in regards to OOP. But that doesn't make it better or worse.
In JavaScript, you don't need to declare an object's properties, like you have to when you use classes. I think that you only want to serialize the form's input values to JSON. I recommend not to use an object that additionally has a nodes property and a Contains method.
If you need to keep a copy of the unserialized object, create two objects:
class Container {
constructor () {
this.nodes = [];
}
indexOf (node) {
return this.nodes.findIndex(n => n.nodeID === node.nodeID);
}
}
Container.nodeID = 0; // think of it as a static property
function extractValues (elements) {
// 'elements' is an array of <input> elements
// the 'container' will be filled and serialized
var container = new Container();
for (var index in elements) {
var element = elements[index];
container[element.name] = element.value;
}
container.nodeID = Container.nodeID++; // give the container a unique ID
return container;
}
var inputs = document.querySelectorAll('input');
var jsonData = new Container();
document.querySelector('button').addEventListener('click', function () {
var newContainer = extractValues(inputs);
var index = jsonData.indexOf(newContainer);
if (index === -1) {
jsonData.nodes.push(newContainer);
} else {
jsonData.nodes[index] = newContainer;
}
var jsonString = JSON.stringify(jsonData, null, ' ');
console.log(jsonString);
});
<input name="containerID">
<input name="containerTitle">
<!-- ... -->
<button>Serialize</button>
Please note: only setting an object's properties doesn't make it to JSON. It's only JSON if it's serialized to a string. I recommend this article. To serialize a JavaScript object, use JSON.stringify.
Edit:
Looking at the edit of your question, I think it might be preferable to create a Container class. Both jsonData and the containers of the form data will be instances of that class. It can contain other containers (nodes), and can get the index of such a nested container using the indexOf method. I implemented this in the above code snippet. Whenever you hit the "Serialize" button, a new container with the current <input>s' contents will be added to jsonData. The JSON form of jsonData will be logged to the console.
I hope this is what you are looking for. To better understand JavaScript OOP,
take a look at some of the articles at MDN.
I receive the following string from the server response：
var jsonData = '[{"firstName":"Bill","lastName":"Gates"},{"firstName":"George","lastName":"Bush"},{"firstName":"Thomas","lastName":"Carter"}]';
I see some jquery plugins can predefine the keys they want
like: index:"firstName", and they get a ul like
<li>Bill</li>
<li>George</li>
<li>Thomas</li>
If index:"lastName", they get a ul like
<li>Gates</li>
<li>Bush</li>
<li>Carter</li>
The only way I know how to parse a json format string is:
var object = JSON.parse(jsonData);
var firstName = object[i].firstName;
var lastName= object[i].lastName;
The plugin pass the index like a parameter
function f(index) {
return object[i].index;
}
How can they achieve this？
Thanks for helping!
You can access object properties with square brackets. JS objects work like arrays in this regard.
var objects = JSON.parse(jsonData),
key = "firstName";
objects.forEach(function (obj) {
var value = obj[key];
// ...
});
So I'm working on a little personal project and I came upon a problem.
I need each day object to hold various dom element objects. These object instances are stored in an array and then that array needs to be stored into localStorage to load later.
The problem is when I do JSON.stringify and then JSON.parse it converts the HTML nodes into objects. So when I try to append element it tells me that the first parameter is not a node.
function save() {
localStorage.days = JSON.stringify(global.days);
localStorage.numberOfDays = global.numberOfDays;
localStorage.totalCount = global.totalCount;
}
function load() {
var parsedDays = JSON.parse(localStorage.days);
parsedDays.forEach(function(day){
document.getElementById("mainPage").appendChild(day.textObject);
});
anyone know how I can put an array of objects which hold elements into localStorage while keeping their node type????
If you will try to stringify dom nodes then it will return "{}".So its not possible to store node as it is inside localstorage.
What you can do is store information regarding nodes inside localstorage and recreate your node from that information and add it in your dom.
You'd probably need to have a property eg 'type' that defines the element type
var elem
parsedDays.forEach(function(day){
elem = document.getElementById("mainPage").createElement(day.type);
elem.attributes = day.attributes;
elem.innerHTML = day.textObject;
});
Or something like that, not too sure without seeing your day object
Use JSON.stringify and JSON.parse
Example Code:
Element.prototype.toJSON = function (){
return {nodeType:this.nodeType, outerHTML:this.outerHTML};
};
function replacer(k,v){
if(v.nodeType===1 && v.outerHTML){
var ele = document.createElement('html');
ele.innerHTML = v.outerHTML;
return ele.removeChild(ele.firstChild);
}
return v;
}
//test
var jstr = JSON.stringify({ele:document.body});
var json = JSON.parse(jstr,replacer);
console.log(jstr);
console.log(json);
/* Helper function to clean up any current data we have stored */
function insertSerializedData(ids, type) {
// Get anything in the current field
current_data = $('#changes').val();
if (!current_data) {
var data = new Array();
data[type] = ids;
$('#changes').val(JSON.stringify(data));
} else {
var data = JSON.parse($('#changes').val());
data[type] = ids;
$('#changes').val(JSON.stringify(data));
}
console.log($('#changes').val());
}
I am using the following function to either add data to a current JSON object or create a new JSON object all together to be used in PHP later. Is the stringify() method only for FF? I am using google chrome and I am being given an empty object when using the conosole.log() function...
Also what happens if you try to store two values with the same key? I assume it will overwrite...so I should add a random math number at the end array in order to keep duplicates from showing up?
Thanks :)
These lines may cause problems:
var data = new Array();
data[type] = ids;
... because arrays in JavaScript are not quite like arrays in PHP. I suppose what you meant is better expressed by...
var data = {};
data[type] = ids;
Besides, current_data seems to be local to this function, therefore it also should be declared as local with var. Don't see any other problems... except that similar functionality is already implemented in jQuery .data() method.
UPDATE: here's jsFiddle to play with. ) From what I've tried looks like the array-object mismatch is what actually caused that Chrome behavior.
I reformatted it a bit, but and this seems to work. It will set the "value" attribute of the #changes element to a JSON string. I assume that the type argument is supposed to be the index of the array which you're trying to assign?
function insertSerializedData(ids, type) {
var changes = jQuery('#changes'), arr, val = changes.val();
if (!val) {
arr = [];
arr[type] = ids;
changes.val(JSON.stringify(arr));
} else {
arr = JSON.parse(val);
arr[type] = ids;
changes.val(JSON.stringify(arr));
}
console.log(changes);
}