JavaScript Object.is()
Summary: in this tutorial, you will learn about the JavaScript Object.is() to check if two values are the same.
The Object.is() behaves like the === operator with two differences:
- -0 and +0
- NaN
Negative zero
The === operator treats -0 and +0 are the same value:
let amount = +0,
volume = -0;
console.log(volume === amount);Code language: JavaScript (javascript)
Output:
trueCode language: JavaScript (javascript)
However, the Object.is() treats +0 and -0 as different values. For example:
let amount = +0,
volume = -0;
console.log(Object.is(amount, volume));Code language: JavaScript (javascript)
Output
falseCode language: JavaScript (javascript)
NaN
The === operator considers NaN and NaN are different values. The NaN is the only number that does not equal itself. For example:
let quantity = NaN;
console.log(quantity === quantity);Code language: JavaScript (javascript)
Output:
false
However, Object.is() treats NaN as the same value:
let quantity = NaN;
console.log(Object.is(quantity, quantity));
Output:
trueSee the following sameness comparison table for reference:
