[compiler/language-service::getScriptVersion] Shouldn't this statement use optional chaining and not non-null assertion operator?

[cp79shark]

ts-jest/src/compiler/language-service.ts

Line 85 in b5dc7cb

const version = memoryCache.files.get(normalizedFileName)!.version

If the file is not in the MemoryCache this will throw. I'm not sure if this is the intended behavior, but it is causing issues for me.

ts-jest/src/compiler/language-service.ts

Lines 87 to 92 in b5dc7cb

	// We need to return `undefined` and not a string here because TypeScript will use
	// `getScriptVersion` and compare against their own version - which can be `undefined`.
	// If we don't return `undefined` it results in `undefined === "undefined"` and run
	// `createProgram` again (which is very slow). Using a `string` assertion here to avoid
	// TypeScript errors from the function signature (expects `(x: string) => string`).
	return version === undefined ? ((undefined as any) as string) : String(version)

The return statement, and the lengthy comment above it, already expects as much is a possibility and will return undefined.

Changing to const version = memoryCache.files.get(normalizedFileName)?.version; will allow a cache miss and return undefined.

[ahnpnl]

Do you have a case when it causes issue ? getScriptVersion is always executed after getScriptFileName (as far as I have observed) so that’s why the ! operator is there.

I’m curious to see which cases it fails. But ya for code perspective, ? should be used instead

[cp79shark]

Heh, I woke up this morning trying to think how I could provide you a minimal repro (source repo is huge and private). The error was only reproducible with a clean repo (delete entire root folder, clone, jest). normalizedFileName was set, just not present in cache. I didn't dig into it too much on the why side since the "fix" was obvious and the sirens of other fires were calling my name.

If there's any info I can provide let me know, but with the PR I'm good. Will just patch local JS until update published. Thanks.

[johnjayhopley]

Has a fix been published for this now?

[ahnpnl]

will be soon, included in 26.0.0