65,005 questions
7585
votes
40
answers
3.4m
views
How do I remove a property from a JavaScript object?
Given an object:
let myObject = {
"ircEvent": "PRIVMSG",
"method": "newURI",
"regex": "^http://.*"
};
How do I remove the property ...
- 98.6k
5157
votes
67
answers
3.1m
views
What is the most efficient way to deep clone an object in JavaScript?
What is the most efficient way to clone a JavaScript object? I've seen obj = eval(uneval(o)); being used, but that's non-standard and only supported by Firefox. I've done things like obj = JSON.parse(...
4136
votes
33
answers
3.8m
views
Checking if a key exists in a JavaScript object?
How do I check if a particular key exists in a JavaScript object or array?
If a key doesn't exist, and I try to access it, will it return false? Or throw an error?
- 54.3k
3247
votes
49
answers
1.5m
views
Detecting an undefined object property
How do I check if an object property in JavaScript is undefined?
- 118k
3082
votes
44
answers
3.1m
views
Length of a JavaScript object
I have a JavaScript object. Is there a built-in or accepted best practice way to get the length of this object?
const myObject = new Object();
myObject["firstname"] = "Gareth";
...
- 37.9k
2536
votes
16
answers
1.6m
views
How can I check if an object has an attribute?
How do I check if an object has some attribute? For example:
>>> a = SomeClass()
>>> a.property
Traceback (most recent call last):
File "<stdin>", line 1, in <...
2494
votes
19
answers
1.3m
views
Calling a function of a module by using its name (a string)
How do I call a function, using a string with the function's name? For example:
import foo
func_name = "bar"
call(foo, func_name) # calls foo.bar()
- 37k
2398
votes
32
answers
1.7m
views
Iterate through object properties
var obj = {
name: "Simon",
age: "20",
clothing: {
style: "simple",
hipster: false
}
}
for(var propt in obj){
console.log(propt + ': ' + obj[propt]);
}
...
- 24.4k
2029
votes
2
answers
2.3m
views
How do I check if an object has a key in JavaScript? [duplicate]
Which is the right thing to do?
if (myObj['key'] == undefined)
or
if (myObj['key'] == null)
or
if (myObj['key'])
kevin
1717
votes
6
answers
468k
views
Why do Python classes inherit object?
Why does the following class declaration inherit from object?
class MyClass(object):
...
- 18.1k
1514
votes
10
answers
1.5m
views
Object comparison in JavaScript [duplicate]
What is the best way to compare objects in JavaScript?
Example:
var user1 = {name : "nerd", org: "dev"};
var user2 = {name : "nerd", org: "dev"};
var eq = user1 == user2;
alert(eq); // gives false
I ...
- 22.4k
1513
votes
11
answers
2.6m
views
1391
votes
23
answers
1.8m
views
Convert JS object to JSON string
If I defined an object in JS with:
var j={"name":"binchen"};
How can I convert the object to JSON? The output string should be:
'{"name":"binchen"}'
- 63.6k
1327
votes
21
answers
916k
views
Difference between ( for... in ) and ( for... of ) statements?
I know what is a for... in loop (it iterates over the keys), but I have heard about for... of for the first time (it iterates over values).
I am confused about for... of loop.
var arr = [3, 5, 7];
arr....
- 23.6k
1248
votes
42
answers
2.4m
views
Converting an object to a string
How can I convert a JavaScript object into a string?
Example:
var o = {a:1, b:2}
console.log(o)
console.log('Item: ' + o)
Output:
Object { a=1, b=2} // very nice readable output :)
Item: [object ...
- 12.5k