Code:
a=[1,2];
b=[];
if(b==0){
console.log('0')
}
if(a==2){
console.log('2')
}
if([]==0){
console.log('3')
}
Output:
0
3
in case if [ ] is considered as an array of length 0 and == is comparing [ ] to its length.Why is [1,2]==2 false?
It's not comparing against the length of the array, it's calling the valueOf function of the object, which (I think) is the same as arr.join('').
console.log(String([].valueOf()) === '');
console.log(String([1, 2].valueOf()) === '1,2');The first one results in '', which is loosely equal to 0.
The second one results in '1,2'.
the == will do some conversation before do the comparison
console.log([] == false) // true
console.log(0 == false) // true
console.log([] == 0) // truealso I suggest you read this question and its answers
[] == 0 == false == ''- read about loose comparison. also read about===