Can you explain how works the Comparison Operators in JS:
"a" > "A" // => why true?
null == undefined; // and here as well?
and some others
null > 0;
null >= 0;
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1 Answer
Strings are compared by their character codes, ie. their positions in the Unicode table.
A is 65, a is 97. Therefore "a" > "A".
== is a loose comparison. null == undefined is a special case, since the abstract equality comparison algorithm explicitly states that true should be returned when comparing these two values:
2. If x is
nulland y isundefined, returntrue.
3. If x isundefinedand y isnull, returntrue.
null > 0 is false, and null >= 0 is true because null, when converted to a number, is zero.
answered May 26, 2014 at 17:02
Niet the Dark Absol
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8 Comments
Felix Kling
null and undefined are not converted when doing null == undefined. The abstract equality algorithm explicitly states that true should be retuned in that case.
user2754035
but: null === 0 will be false?
Felix Kling
@user2754035: You can just type it in the console and find out. But yes, it's
false since null and 0 are of different data types. If you want to know what happens when you compare two values with === or ==, have a look at the specification: es5.github.io/#x11.9.3 .
Niet the Dark Absol
@Tyblitz Sadly,
+rep means nothing here :p I already have my +200 for the day. Thanks for the upvote though!Felix Kling
Are you going to fix the part about
null and undefined? |