I was checking this question Javascript Deep Comparison The solution of the question asker did not convince me so I tried to analyze the problem and came up with that
var obj = {here: 2};
console.log(deepEqual(obj, obj));
// → true
console.log(deepEqual(obj, {here: 1}));
// → false
console.log(deepEqual(obj, {here: 2}));
// → true
function deepEqual(a,b)
{
if( (typeof a == 'object' && a != null) &&
(typeof b == 'object' && b != null) )
{
var count = [0,0];
for( var key in a) count[0]++;
for( var key in b) count[1]++;
if( count[0]-count[1] != 0) {console.log('1');return false;}
for( var key in a)
{
if(!(key in b) || !deepEqual(a[key],b[key])) {console.log('2');return false;}
}
for( var key in b)
{
if(!(key in a) || !deepEqual(b[key],a[key])) {console.log('3');return false;}
}
}
console.log('a:'+a+' b:'+b);
return a===b;
}
obj === { here:2 }
This code fails the last test ( console.log(deepEqual(obj, {here: 2})) ) but the logic of considering objects deeply equal if they have respectively equal keys and values despite being different instances in memory does not convince me. Is there's a problem with my 'solution' or the mistake lies in the presumptions of the exercise? Is the code mentioned in the question I linked valid?
Resources that hikinthru forgot to mention ( http://eloquentjavascript.net/04_data.html#exercise_deep_compare )