JavaScript Quiz Question #1: Array Sort Comparison

#javascript #challenge #webdev #programming

Consider the following arrays. What gets logged in various sorting conditions?

const arr1 = ['a', 'b', 'c'];
const arr2 = ['b', 'c', 'a'];

console.log(
  arr1.sort() === arr1,
  arr2.sort() == arr2,
  arr1.sort() === arr2.sort()
);

A) true true true
B) true true false
C) false false false
D) true false true

Put your answer in the comments!

Top comments (19)

Paula Gearon • Apr 23 '20

The question, as asked, is misleading. Arrays don't compare in Javascript! 🙂 Also, while the arr1 and arr2 values don't change, the arrays they refer to do, so the const is likely to trip some people up.

The .sort function returns the array that was sorted, so comparing arr1.sort() to arr1 is just comparing the array reference to itself. The same goes for arr2 on the next line (the use of == is another potential red herring, since the arrays are the same, so type conversion doesn't happen). Finally, while the sorted arrays contain the same info, arr1 is a different object to arr2, so the final comparison is false.

Nick Scialli (he/him) • Apr 23 '20

Which part of the question is misleading? Can you quote it here so I can fix it?

Paula Gearon • Apr 23 '20

Sorry... my wording was probably unclear. I mean that it's a trick question. It has red herrings in it.

The misleading nature is where you state: "...in various sorting conditions?"
This misleads the reader since sorting is irrelevant here. The only real relevance is that the sort() method returns the original array object.

YogeshMedz • Apr 22 '20

B). true true false
Because === is used for comparison between two variables but this will check strict type, which means it will check datatype and compare two values and == is used for comparison between two variables irrespective of the datatype of variable.