Learning JavaScript in depth, this repository contains notes and code for the concepts that I find useful and insightful :)
Important Note: Precedence of && is more than || |
JavaScript’s way of handling &&, || is completely different when it comes to
non-boolean values. More appropriate way of explaining would be it evaluates
from left to right fashion and instead of returning a boolean value it returns
actual value stored in the operand itself.
console.log(null || "hello" || undefined) // returns "hello"
// can also be used in place of `if`
(3 > 0) && alert(x) // this executes alert(x)
(1 < 0) && alert(x) // this doesn't
JavaScript defines an unusual operator ??, which might be seen in some open source project basically it returns the first argument (from left to right) which is neither undefined nor null. For example:
console.log(null ?? "hello") // "hello"
console.log("hello" ?? "trudy") // "hello" again!
console.log(null ?? undefined) // undefined
console.log(undefined ?? null) // null
Precedence: Just lower than ||.
JavaScript enforces the use of “parantheses” with &&, || and ?? together.