Calculating sums
JavaScript
Read fire tipThe nullish-coalescing operator
JavaScript
In JavaScript, we can use || to set default values for variables. Besides null and undefined, this also overrides other falsy values like 0, false, and empty strings. The nullish coalescing operator ?? only overrides null and undefined.
27 || "default" // ⇒ 27 good
true || "default" // ⇒ true good
"truthy!" || "default" // ⇒ "truthy!" good
null || "default" // ⇒ "default" good
undefined || "default" // ⇒ "default" good
0 || "default" // ⇒ "default" bad (overrides real value)
false || "default" // ⇒ "default" bad (overrides real value)
"" || "default" // ⇒ "default" bad (overrides real value)
27 ?? "default" // ⇒ 27 good
true ?? "default" // ⇒ true good
"truthy!" ?? "default" // ⇒ "truthy!" good
null ?? "default" // ⇒ "default" good
undefined ?? "default" // ⇒ "default" good
0 ?? "default" // ⇒ 0 good (keeps real value)
false ?? "default" // ⇒ false good (keeps real value)
"" ?? "default" // ⇒ "" good (keeps real value)