This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
javascript test for existence of nested object key
In JavaScript, is there an easier way to check if a property of a property exists?
I've been searching for an elegant way to verify if the entire object path is defined.
For example: person.positions.values[0].company.name
On every step of the way, after the person, it can be undefined.
Can this be done without actually going through them one by one?
Thank you.
Related
This question already has answers here:
How is almost everything in Javascript an object?
(6 answers)
Why does a primitive variable act like an Object? [duplicate]
(3 answers)
javascript: do primitive strings have methods?
(2 answers)
Closed 2 years ago.
I have this question in mind since I started learning JavaScript last month.
What I have tried?: I researched for it online almost on all good sites but didn't get satisfactory answer in laymans language.
Question: When I create variable let suppose
let name = "mit"
name.toUpperCase()
I am using dot notation to access the method here and I know we use it for something in object. I was confused if the browser creates different object for name variable (which is of string data type here) or what?
This question already has answers here:
How do I check if a variable is an array in JavaScript?
(24 answers)
How can I check if an object is an array? [duplicate]
(51 answers)
Closed 3 years ago.
I was reading this question about how to check if a variable is an Array in Javascript, and this answer proposes several solutions:
1. variable.constructor === Array
2. Array.isArray(variable)
3. variable instanceof Array
The post has several updates and they touch on the efficiency of the different solutions, but between the post and its comments it isn't entirely clear which solution is the most efficient. I'm hoping to clarify which of these solutions provides the most efficient check for whether or not a variable is an Array in JavaScript.
Edit: I'd like to note that this question is about the performance of checking whether or not a variable is an Array and not how to check if a variable is an Array. Considering all the noise in the linked question, I believe there is value to the question.
Thanks to the comments I received, I realized I missed a link to a benchmark, which I then edited to determine that variable instanceof Array is the most efficient of the solutions I was asking about in my question when using Chrome 74. Here is the benchmark.
This question already has answers here:
Variable name length vs performance
(2 answers)
Closed 6 years ago.
Is it possible that a long method or variable name slows down your javascript program a bit?
I wanted to ask because I am currently working on a program where i have a very long method identifier and I wonder if I should shrink it. It would however make my code not so clear anymore.
I know it doesn't matter for compiled languages but what about javascript?
P.S. I do not plan to use a minifier.
Generally, function name length, variable name length, etc, should have no bearing on performance, unless you're talking name length in hundreds of thousands of characters.
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
Huge Integer JavaScript Library
Suppose I want the exact value for 2^1000. How am I supposed to get the entire value? Maybe storing it in a string every time the multiplication is done, but it will still eventually go over 10 digits! Is there any way, or does ECMAScript just not support this?
Math.pow(2,1000)
returns
1.0715086071862673e+301
how accurate do you need this to be?
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Creating a new Location object in javascript
If the user inputs a string that is a URL, what's the easiest way to turn it into a Location object (like window.location) so I can use methods and properties like obj.hostname?
Don't know if you can create a Location object, but this article explains how to use an anchor tag for the same effect:
http://james.padolsey.com/javascript/parsing-urls-with-the-dom/