I am experiencing an issue with the following code snippet:
let count: number | undefined | null = 10;
count = null;
let result: string | undefined | null = count?.toFixed(2);
console.log(`Result: ${result}`);
The error message I received is as follows:
error TS2339: Property 'toFixed' does not exist on type 'never'.
On the other hand, the following code successfully compiles and outputs to the console as expected:
let count: number | undefined | null = 10;
if (1) {
count = null;
}
let result: string | undefined | null = count?.toFixed(2);
console.log(`Result: ${result}`);
Result: undefined
After analyzing this situation, I realized that in the first example, the compiler incorrectly infers that count will always be null. It is interesting to note how the compiler's static analysis lacks consistency, even in cases where the condition of the if statement is a constant value.
Inquiry
I wonder if there is a specific theoretical or design rationale behind this error message (which may indicate a misunderstanding on my part), or if it was simply a questionable decision to treat this more like a severe error rather than a warning, especially given the limited static analysis capabilities demonstrated in the second example?