Does tsc give error for code like this with some tscconfig rules?
function buildName(firstName: string, lastName?: string) {
return firstName + " " + lastName;
}
I think if there is no code to check lastName is not undefined, there must be tsc compiling error. How can I get tsc to give error on compililation.
Concatenating with a variable that contains undefined
is weird, but not forbidden by JS, so it won't throw a TS error.
But usually it's not what you want, and indicates a problem. Therestrict-plus-operands TSLint or ESLint rule forbids this:
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.