What is the output of this JavaScript snippet? ([] == false)

Question

console.log([] == false);

Accepted Answer

true

Loose equality between an object and a boolean first converts the boolean to a number: false becomes 0. Then [] (an object) is converted to a primitive, which for arrays means joining their elements into a string — an empty array joins to the empty string ''. Now it's '' == 0, a string vs a number, so '' is converted to a number too, giving 0 == 0, which is true. Every step quietly changes the type until both sides finally agree.

#8: [] == false