AI solution for JavaScript Quiz on BFE.dev
56. to primitive

The code outputs the following using console.log:

// case 1
101
100

// case 2
201
NaN

// case 3
101
100
100

// case 4
2
1

// case 5
2
NaN

Explanation:

• In case 1, obj1's valueOf method returns 1, so obj1 + 1 equals 2. parseInt(obj1) returns 100.
• In case 2, obj2's Symbol.toPrimitive method takes precedence over the valueOf and toString methods. It returns 200, making obj2 + 1 equal to 201. However, parseInt(obj2) returns NaN since the string '100' is not a valid number.
• In case 3, when trying to convert obj3 to a number, JavaScript first tries to use the valueOf method, but it's not defined. Then it uses the toString method and returns the number 100, so +obj3 equals 100. obj3 + 1 concatenates the string '100' and the number 1, resulting in '1001'. parseInt(obj3) returns 100.
• In case 4, obj4's valueOf method returns 1, so obj4 + 1 equals 2. parseInt(obj4) returns 1.
• In case 5, obj5's Symbol.toPrimitive method returns '100' when the hint is 'string' and 1 otherwise. obj5 + 1 converts obj5 to a string ('100') and concatenates it with the number 1, resulting in '1001'. parseInt(obj5) returns NaN, because it receives a non-string value.