Basically I have a complex object that retrieves the GPT API (google publisher tag) with this function:
googletag.pubads().getSlots();
The object value is something like this:
I need to know if there is a way to compare the value of each property with an X value without getting a problem of recursivity (because the object is huge and i need to to that validation several times)
Also, I tried to convert that object into a JSON with JSON.stringify(), and then tried to get the value with a regex, faster, but with this option, I have the problem with Cyclic Object Value.
Any suggestions ?
it's more simple. try it to convert it into an array and later use a filter for comparative with your value.
var objGoogle = {};
var arrayObjectGoogle = [objGoogle];
var filter = arrayObjectGoogle.filter(function(obj){
obj.yourAttr == yourValue; });
this will give you a second array with the values found it. later, index the array for pick up the value do you need.
Related
I am trying to figure out how to retrieve the values of a json of which i do not know the number of elements.
Example:
my json can be something like
var json = ["fixelement1":"value1","fixelement2":"value2","fixelement3":"value3","variableelement4":"value4","variableelement5":"value5"]
or
var json =["fixelement1":"value1","fixelement2":"value2","fixelement3":"value3","variableelement7":"value7","variableelement8":"value8", "variableelementN":"valueN"]
the only thing that I know is that the first 3 elements are always the same.
I use .indexOf() to search a value in fixelement3. What I would like to do is, if I find the element, I would like to retrieve the name of all the following elements (which number is variable and that are unknown) and their values.
javascript or jquery would work for me, but I have no idea..
thank you in advance!
var json ={
"fixelement1":"value1",
"fixelement2":"value2",
"fixelement3":"value3",
"variableelement7":"value7",
"variableelement8":"value8",
"variableelementN":"valueN"
}
for(prop in json){
console.log('key ======> value', prop, '=====>', json[prop]);
}
I have a variable called uids
var uids = [];
Then I write some value to it property
uids[16778923] = "3fd6335d-b0e4-4d77-b304-d30c651ed509"
But before it
if (!uids[user.id]) {
uids[user.id] = generateKey(user);
}
This thing behaves ok. If I try to get the value of it property
uids[currentUser.id]
It will give me a value of this property. If I try to call some methods like
Object.keys(uids);
It will give me, what I expected. And here the mystery comes...
uids;
RAM rest in piece. See the node eating ram
I am very confused now. What's wrong?
This is because you are creating a huge array and node will reserve memory for it - who knows what comes. I'd say that's a scenario where you would use a Map (or a plain object, but Map feels better here.
var uids = new Map();
var key = 456464564564654;
if (! uids.has(key)) {
uids.set(key, generateKey(user))
}
You are creating an empty array (length is zero), then you assign some value to an arbitrary index. This will make the array grow as big as the index and assign the value to that index. Look at this example using node.js REPL:
> var a = []
undefined
> a[5] = "something"
'something'
> a
[ , , , , , 'something' ]
> a.length
6
Instead of creating an array, you could create a Map() or an common javascript object (singleton). Javascript objects behave like Maps but only Strings can be used as keys. If you assign a Number to be key, javascript will convert it to String automatically.
Personally, I would go with objects because they perform better. Instantiating an object takes longer than instantiating a Map (and it doesn't seem like you need to create several groups of "uids"), but once done, adding new keys and retrieving values from any key in faster when using common objects. At least that's how things go in my node.js v6.7.0 on ubuntu 14.04 but you could try for yourself. And it would also make the least alteration to your code.
var uids = {} // common/ordinary empty javascript object instead of array.
if (!uids[user.id]) { // getting value from one key works the same.
uids[user.id] = generateKey(user) // assignment works the same.
}
////
uids[16778923] = "3fd6335d-b0e4-4d77-b304-d30c651ed509" // key will be "16778923".
uids[16778923] // getting value for key "16778923" can be done using 16778923 instead of "16778923".
////
uids[currentUser.id] // still returning values like this.
Object.keys(uids) // still returning an array of keys like this. but they are all Strings.
I'm making a web app where a user gets data from PHP, and the data consists of MySQL rows, so I want to save the used ones in a global variable, something like a buffer, to prevent extra AJAX requests.
I'm doing this right now :
window.ray = []; // global variable
$(function(){
data = getDataWithAjax(idToSearch);
window.ray[data.id] = data.text;
});
but when the id is big, say 10 for now, window.ray becomes this :
,,,,,,,,42
so it contains 9 unnecessary spots. Or does it? Is it only visible when I'm doing console.log(window.ray);
If this is inefficient, I want to find a way like PHP, where I can assign only indices that I want, like :
$array['420'] = "abc";
$array['999'] = "xyz";
Is my current way as efficient as PHP, or does it actually contain unnecessary memory spots?
Thanks for any help !
Use an object instead of an array. The object will let you use the id as the key and be more efficient for non-sequential id values.
window.ray = {}; // global variable
$(function(){
data = getDataWithAjax(idToSearch);
window.ray[data.id] = data.text;
});
You can then access any element by the id:
var text = window.ray[myId];
If you are assigning values directly by property name, then it doesn't make any difference in terms of performance whether you use an Array or an Object. The property names of Arrays are strings, just like Objects.
In the following:
var a = [];
a[1000] = 'foo';
then a is (a reference to) an array with length 1,001 (always at least one greater than the highest index) but it only has one numeric member, the one called '1000', there aren't 1,000 other empty members, e.g.:
a.hasOwnProperty['999']; // false
Arrays are just Objects with a special, self–adjusting length property and some mostly generic methods that can be applied to any suitable object.
One feature of sparse arrays (i.e. where the numeric properties from 0 to length aren't contiguous) is that a for loop will loop over every value, including the missing ones. That can be avoided and significant performance gains realised by using a for..in loop and using a hasOwnProperty test, just like an Object.
But if you aren't going to use any of the special features of an Array, you might as well just use an Object as suggested by jfriend00.
I am new to jquery and trying something and got stuck at it,
My problem is i have object with array in it i am not able to find the way to access that array from the object
//My object is shown in debugging time is as below
cache:object
0001-:Array[2]
0:value1,
1:value2
_prto_:object
and i want to access the value1 and value2 from the 0001- array from that object is there way to access that array. Any help would be great. I know with $.each i can loop through it and and then again access the array but is there any other way to do it.
You can access it like, and keep in mind that you should use bracket notation in this context, since your keys having a starting character as a number.
cache['0001-'][0] //first element on that array
cache['0001-'][1] //second element
A workaround for your new requirement,
var cache = {'0001-' : [0,1]};
var xKeys = Object.keys(cache);
console.log(xObj[xKeys[0]][0]);
console.log(xObj[xKeys[0]][1]);
I had a question about best practice for passing a list of XML xpath values to a function.
I'm just a beginner programmer and am just learning javascript.
What I want to do is define an object with criteria (done this okay), and a list of results I want back from a query, both of which that can be passed to a function.
The following is working, but I'm thinking that probably sending the xpath as the key in the object is probably not the best idea, with null values. I get back an object from the function with the keys I sent and the values.
var myCriteria = { prospect_id : 98888158, type : 13};
var myResults = { 'total_results':null , 'visitor_activity/id':null };
myResults = pardotQuery(authentication, 'visitorActivity', myCriteria, myResults);
I thought about just passing it in as an array, then converting it into an object that gets returned with keys, and values.
Please advice what would be best.
Thanks.