We know what the difference between ==
and ===
is - basically, ===
prevents Javascript engine to convert one of the parameter for making both parameters of the same type. But now, in ES6, came a new operator - Object.is
which is a bit confusing (or maybe ===
is now confusing..)
From Mozila website (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness) we can see the difference:
Sameness Comparisons:
x y == === Object.is
+0 -0 true true false
NaN NaN false false true
So, for me, looks like Object.is
is even more strict in comparing parameters, if so, question raises - how unstrict was ===
(called "Strict Equality") :)
From the article you linked:
When to use Object.is versus triple equals
Aside from the way it treats NaN, generally, the only time Object.is's special behavior towards zeros is likely to be of interest is in the pursuit of certain meta-programming schemes, especially regarding property descriptors when it is desirable for your work to mirror some of the characteristics of Object.defineProperty. If your use case does not require this, it is suggested to avoid Object.is and use === instead. Even if your requirements involve having comparisons between two NaN values evaluate to true, generally it is easier to special-case the NaN checks (using the isNaN method available from previous versions of ECMAScript) than it is to work out how surrounding computations might affect the sign of any zeros you encounter in your comparison.