This question already has answers here:
console.log() async or sync?
(3 answers)
console.log() shows the changed value of a variable before the value actually changes
(7 answers)
Closed 5 years ago.
Please share your thoughts regarding below outputs.
var a = '';
console.log(a); //this logs nothing as expected.
a = 'triven';
var a = {};
console.log(a); // How javascript is aware of property here that is defined below.
a.name = 'triven';
I think you're looking for console.dir().
console.log() doesn't do what you want because it prints a reference to the object, and by the time you pop it open, it's changed. console.dir prints a directory of the properties in the object at the time you call it.
The JSON idea below is a good one; you could even go on to parse the JSON string and get a browsable object like what .dir() would give you:
console.log(JSON.parse(JSON.stringify(obj)));
Related
This question already has answers here:
Array.includes() to find object in array [duplicate]
(8 answers)
Object comparison in JavaScript [duplicate]
(10 answers)
How to determine equality for two JavaScript objects?
(82 answers)
Closed 9 months ago.
I'm trying to use arr.filter() to find the missing element between two arrays, this has been answered plenty of times and i've seen threads like this one Finding missing element in two array for javascript that explain it actually very well. For some reason thought, i cant seem to get this to work.
This is my code
var x = [{Number:1},{Number:2},{Number:3}]
var y = [{Number:1},{Number:2}]
function getDifference(x,y){
x.filter(function(object,index,arr){
console.log(object,index,arr)
if(!y.includes(object)){
// print object
console.log(object) // <-- Prints all 3, should just print the missing one.
}
})
}
getDifference(x,y)
Basically, it just needs to print out the missing object. Which in this case, is {Number:3}
Instead, it prints every object.
I've tried with the code in the thread that i linked above, and still was having trouble. Not sure what i'm not understanding with it.
This question already has answers here:
Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference
(7 answers)
Chrome DevTools - inconsistent array length
(1 answer)
Closed 4 years ago.
When i see my book object in console it shows array but when i try to iterate it does not iterartes in loop.
console.log(book);// logs array of length 6
console.log(typeof book);// logs -> object
console.log(book.length);// logs 0
//this for loop does not iterates.
for(let i of book)
{
//logic
}
Please help me how to iterate?
my book object looks like below on console.
let i of book is wrong. Since it is an array of object, try to do below.
book.forEach( function (bookItem)
{
Your logic
});
This question already has answers here:
Chrome/Firefox console.log always appends a line saying 'undefined'
(9 answers)
Closed 7 years ago.
I have a JavaScript object:
function Thing() {
this.number = 4;
}
I create an instance and assign a new property:
var myThing = new Thing();
myThing.newProperty = 5;
console.log(myThing.newProperty);
and the output is:
5
undefined
Why is the output also printing undefined?
You don't need to type console.log() into the console. If you type in a variable, it'll print its value.
When you do console.log(myThing.newProperty); in the console, it runs it and shows you its return value.
5 is shown because you ran console.log. undefined is shown because that's console.log's return value.
This question already has answers here:
How to use a variable for a key in a JavaScript object literal?
(16 answers)
Closed 7 years ago.
I have an object and a few variables I'd like nested inside the variable but for some reason I can only ever get the first nest. Anything after that gives me an error stating that it couldn't read because it was undefined:
var date = 10;
var timestamp = 100;
Que[date] = {timestamp:{"test":"test"}};//this returns {10:{"timestamp":{"test":"test"}}}; for some reason
Que[date][timestamp] = {"test":"test"}; //errors saying, cannot read '100' undefined
console.log(Que);
I'm not sure why this is happening and I'd really like to resolve it with simple means. Btw the Que variable is global inside another script and predeterminietly contains {"10":{"24":{"1":"test"}}}; which is likely why the date variable does work but the timestamp variable doesn't. Any suggestions?
EDIT:
date, and timestamp are both declared outside of the object, however i wish to use them as key's inside of the object..
uppon reading the mod suggested post and implementing what it contained, i ended up with another error
Que = {[date]:{[timestamp]:{"test":"test"}}};//this results in an unexpectd token error located at the [ before date
I think there are more questions to be asked based off of your code snippet, but in your example timesheet is not defined, you can reference the key inside your JSON by using
Que[date]["timesheet"]
To access the object inside. The key that you're looking up with the [] notation should be a string.
This question already has answers here:
How can I access and process nested objects, arrays, or JSON?
(31 answers)
JavaScript property access: dot notation vs. brackets?
(17 answers)
Closed 8 years ago.
I need to know why this isn't working. My Javascript code accesses a variable in an object. But it appears not to be working, partly because I can't figure out the syntax.
var obj = {
size:"small",
big:false,
thing:true
}
alert(obj[size]);
I'm just not sure if I got the syntax right…
This will work here.
obj.size //returns small
OR
obj["size"] //returns small
OR
var my_var = "size"
obj[my_var] //returns small
You can reference object values either by:
obj["size"]
or
obj.size
However, there is an exception. For instance, if you have following object with a number key: (Note: key is still a string even if it's defined this way):
var obj = {
1: true
};
You can retrieve it's value only by using: obj["1"]
Hence, using obj.1 will cause a syntax error.
Therefore, your code works if you change it to e.g.: alert(obj["size"]); but I prefer to use console.log(obj["size"]); for debugging. At least, if you are playing with node.js as your tags indicates.
Cheers.