1.Javascript == operator?
JavaScript has two equality operators: "==" and "===". Both operators are used to compare values, but they behave differently when it comes to type coercion. In this article, we'll explore the differences between the two operators and when to use each.
The "==" operator (loose equality) The "==" operator performs type coercion before comparing values. This means that if two values have different types, JavaScript will attempt to convert one of the values to a type that matches the other.
For example:
5 == "5" // true
console.log(21 == 21); // true
console.log(21 == '21'); // true
console.log('food is love'=='food is love'); // true
console.log(true == 1); // true
console.log(false == 0); // true
console.log(null == undefined); // true
console.log(21 == 32); //false
console.log(21 == '32'); //false
console.log(true == 0); //false
console.log(null == false); //false
In this case, the number 5 is compared to the string "5". JavaScript converts the number to a string, so the comparison returns true.
The "==" operator can be useful when you want to compare values, but don't care about the types of those values. However, it can also lead to unexpected results if you're not aware of the type of coercion.
2. Javascript === operator?
The "===" operator (strict equality) The "===" operator, on the other hand, does not perform type coercion. It only returns true if both values have the same type and the same value.
For example:
5 === "5" // false
console.log('hello world' === 'hello world'); //true
console.log(true === true); //true
console.log(5 === 5); //true
console.log(true === 1); //false
console.log(true === 'true'); //false
console.log(5 === '5'); //false
In this case, the number 5 is compared to the string "5". Since the two values have different types, the comparison returns false.
The "===" operator is the preferred equality operator in JavaScript. It provides predictable results, and it's less likely to lead to unexpected behavior due to type coercion.
When to use "==" and "==="? In general, it's recommended to use the "===" operator for all comparisons, unless you specifically need to compare values with type coercion.
For example, if you're writing a function that checks if a user has entered a valid password, you should use "===". This ensures that the password is a string and has the correct value.
On the other hand, if you're writing a function that adds two values together, you may use "==". This allows you to add numbers and strings, as JavaScript will perform type coercion and convert the string to a number.
In conclusion, the "===" operator is more strict and less likely to lead to unexpected behavior, while the "==" operator allows for type coercion. When in doubt, it's best to use "===". By doing so, you can write more predictable and maintainable code.
Conclusion
The == operator compares two equal values without checking the type and returns true if the values are equal, else false. The === operator checks both the type and the values and returns true if both are the same, else false.