Hint
Arrays coerce to strings via .join(","). []==![] is true — one of JS's most infamous "wat" moments.
console.log([] == ![]);
console.log([] == false);
console.log(+[]);
console.log(+[1]);
console.log(+[1,2]);true true 0 1 NaN
Explanation: []==![]: ![] is false ([] is truthy). []==false. [].toString()="" then +"" =0. false→0. 0==0 → true.
[]==false: [].toString()="", +""=0, false→0, 0==0→true.
+[]: []→""→0.
+[1]: [1]→"1"→1.
+[1,2]: [1,2]→"1,2"→NaN.
Key Insight: Arrays coerce to strings via .join(","). []==![] is true — one of JS's most infamous "wat" moments.