JS-032
Beginner4 min~4 min read#equality#loose-equality#strict-equality
== vs ===
Similar, but different
Goal
Understand the difference between == and === in JavaScript.
Explanation
- == checks equality after possible type conversion.
- === checks both value and type without automatic conversion.
- Because of this, == can sometimes give unexpected results.
- For example, 0 == false returns true because JavaScript converts types before comparing.
- In most cases, it is safer to use ===.
Analogy
== is like a judge who says "they are close enough." === is like a strict judge who checks both appearance and document type.
Code
console.log(0 == false);
console.log(0 === false);Result: true false
Common mistake
Beginners often think == and === are almost the same. In reality, the difference matters a lot because of automatic type conversion.
Remember
- ✦ == may convert types.
- ✦ === does not convert types.
- ✦ In most cases, use ===.
Quick Quiz
Which operator checks both value and type?