In the following code, TS infer type of y as string while it's undefined. Is it possible to fix it without explicitly define string|undefined type for y?
const x: string[] = []
const y = x[0]
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1 Answer
Set "noUncheckedIndexedAccess": true in tsconfig.json:
"Turning on noUncheckedIndexedAccess will add undefined to any un-declared field in the type": https://www.typescriptlang.org/tsconfig#noUncheckedIndexedAccess
// with noUncheckedIndexedAccess=true
const x: string[] = [];
const y = x[0];
y; // const y: string | undefined