Why it's valid to get element by indexing an object, but can't check if this element is in the object?
187
How do I check if an array includes a value in JavaScript?
39781
Why does the is operator return false when given null?
73546
Iterating over array of objects javascript - odd behaviour?
144960
Why is Javascript's "in" operator consistently slower than strict member comparison to undefined?
64597
How to get a JavaScript object's class?
22311
How to validate that an object (whose locator we don't know since it is not present) is not present in a page
1937
How to find the index of an element in an array in Java?
140448
How can I get LINQ to return the index of the object which has the max value in a collection?
138295
How can I get the full object in Node.js's console.log(), rather than '[Object]'?
115418
Are functions valid keys for javascript object properties?
140826
Force JavaScript exception/error when reading an undefined object property?
136224
Python: Selecting object by name in 2.8
58600
indexOf method in an object array?
3526
How to determine equality for two JavaScript objects?
126196
How to check if an object is an array?
68770
How can I find the keys of an object?
152971
Why variable = object doesn't work like variable = number