This question already has answers here:
How can I list all the properties of Math object?
(3 answers)
Closed 8 years ago.
Is there a nice way to convert Math object into "real" javascript object?
I want to use Object.keys on Math object. Is that possible to not hardcode it all the way down?
The properties of Math are not enumerable, so Object.keys(Math) returns an empty array.
However, you can use
Object.getOwnPropertyNames(Math)
It will produce something like
["toSource","abs","acos","asin","atan","atan2","ceil","clz32","cos","exp","floor","imul","fround","log","max","min","pow","random","round","sin","sqrt","tan","log10","log2","log1p","expm1","cosh","sinh","tanh","acosh","asinh","atanh","hypot","trunc","sign","cbrt","E","LOG2E","LOG10E","LN2","LN10","PI","SQRT2","SQRT1_2"]
Related
This question already has answers here:
How to get a key in a JavaScript object by its value?
(31 answers)
How do I check if an array includes a value in JavaScript?
(60 answers)
How can I access and process nested objects, arrays, or JSON?
(31 answers)
Closed 29 days ago.
I'm trying to do a for in in an obj Json array looking for a variable, specify the following example. Thank you very much in advance.
I want to consult which division a certain team is in "Vasco".
I wanted to understand what better way.
{"table":{"1° Division":["Flamengo","Goiás","Palmeiras"], "2° Division": ["Real","Barc","Madri"], "3°Division": ["Vasco","Itunbi","Recife"]}}
if you treat the json as an array it should come easy for you.
after that you can use a shorting algorithm
This question already has answers here:
Get all instances of class in Javascript
(6 answers)
Can I get all instances for a prototype in javascript?
(2 answers)
Closed 1 year ago.
This is not a browser or DOM specific question. If a number of child objects are instantiated from a JavaScript class, is there an easy way to iterate through those objects? I know there might be some way to do this through the Object prototype chain, but I am not sure how to do this or how to do it efficiently. Would this be different in Node versus a browser window?
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:
Safely turning a JSON string into an object
(28 answers)
Closed 3 years ago.
For example: '[test,abc,123]'. How do you turn that into a standard javascript array that can be iterated?
This will work, but really you should fix your input to give you real JSON as is noted in the comments.
console.log(JSON.parse('["test","abc",123]'));
This question already has answers here:
How can I check if an object is an array? [duplicate]
(51 answers)
Closed 6 years ago.
If so, how can I detect the difference between them.
I've noticed that you can't do typeof Array hence I'm looking for different solution to see the difference.
You can detect if a variable is an array by using Array.isArray(yourArray).