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Code Foundations Start your programming journey with an introduction to the world of code and basic concepts.
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The nullish coalescing operator (??) in JavaScript only considers null or undefined as "nullish" values. If the left-hand side is any other value, even falsy values like "" (empty string), 0, or false, it will not use the right-hand side:
javascript - When should I use ?? (nullish coalescing) vs || (logical ...
Novice JavaScript developers need to know that the "not not" operator is using implicitly the original loose comparison method instead of the exact or operators and also the hidden cast operation that is happening behind the scenes and I show it in the example I provide.
What does the !! (double exclamation mark) operator do in JavaScript ...
JavaScript arrow functions are roughly the equivalent of lambda functions in python or blocks in Ruby. These are anonymous functions with their own special syntax and operate in the context of their enclosing scope.