💅 noInvalidUseBeforeDeclaration does not raise an error in some complex contexts

[th1nkful]

Environment information

CLI:
  Version:                      1.6.1
  Color support:                true

Platform:
  CPU Architecture:             aarch64
  OS:                           macos

Environment:
  BIOME_LOG_DIR:                unset
  NO_COLOR:                     unset
  TERM:                         "xterm-256color"
  JS_RUNTIME_VERSION:           "v20.11.1"
  JS_RUNTIME_NAME:              "node"
  NODE_PACKAGE_MANAGER:         "pnpm/9.0.6"

Biome Configuration:
  Status:                       Loaded successfully
  Formatter disabled:           false
  Linter disabled:              false
  Organize imports disabled:    false
  VCS disabled:                 true

Linter:
  Recommended:                  true
  All:                          false
  Rules:                        a11y/all = false
                                complexity/noBannedTypes = "off"
                                complexity/noForEach = "off"
                                complexity/noStaticOnlyClass = "off"
                                complexity/noUselessThisAlias = "off"
                                complexity/useFlatMap = "off"
                                complexity/useOptionalChain = "off"
                                correctness/noUndeclaredVariables = "error"
                                correctness/noUnusedImports = "error"
                                correctness/useExhaustiveDependencies = "off"
                                performance/noAccumulatingSpread = "off"
                                performance/noDelete = "off"
                                security/noDangerouslySetInnerHtml = "off"
                                style/noInferrableTypes = "off"
                                style/noNonNullAssertion = "off"
                                style/noParameterAssign = "off"
                                style/useEnumInitializers = "off"
                                style/useNodejsImportProtocol = "off"
                                style/useNumberNamespace = "off"
                                suspicious/noConfusingVoidType = "off"
                                suspicious/noConsoleLog = "error"
                                suspicious/noEmptyInterface = "off"
                                suspicious/noExplicitAny = "off"
                                suspicious/noShadowRestrictedNames = "off"
                                suspicious/noThenProperty = "off"

Workspace:
  Open Documents:               0

Rule name

noUndeclaredVariables

Playground link

https://biomejs.dev/playground/?lintRules=all&code=aQBtAHAAbwByAHQAIABQAHIAbwBtAGkAcwBlAHMAIABmAHIAbwBtACAAJwBiAGwAdQBlAGIAaQByAGQAJwA7AAoACgBjAG8AbgBzAHQAIABnAGUAdABQAGEAZwBlAGQAQwBvAG4AdABlAG4AdABzACAAPQAgAGEAcwB5AG4AYwAgACgAYwB1AHMAdABvAG0AZQByAEkAZAAsACAAbwBwAHQAaQBvAG4AcwApACAAPQA%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%2BAFsAXQAgAD0AIABbAF0AOwAKAAoAIAAgAGEAdwBhAGkAdAAgAFAAcgBvAG0AaQBzAGUAcwAuAHAAYQByAGEAbABsAGUAbAAoAGEAYwB0AGkAbwBuAEkAdABlAG0AcwBHAHIAbwB1AHAAZQBkACwAIABhAHMAeQBuAGMAIAAoAGkAdABlAG0AcwApACAAPQA%2BACAAewAKACAAIAAgACAAYwBvAG4AcwB0ACAAYwBvAG4AdABlAG4AdABJAHQAZQBtAHMAIAA9ACAAYQB3AGEAaQB0ACAAZwBlAHQAUABhAGcAZQBkAEMAbwBuAHQAZQBuAHQAcwAoAGMAdQBzAHQAbwBtAGUAcgAuAGkAZAAsACAAewAKACAAIAAgACAAIAAgAGkAZABzADoAIAAgAGkAdABlAG0AcwAuAG0AYQBwACgAKABpAHQAZQBtACkAIAA9AD4AIABpAHQAZQBtAC4AaQBkACkALAAKACAAIAAgACAAIAAgAHQAaQBtAGUAegBvAG4AZQAsACAALwAvACAALQA%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%3D

Expected result

Expected biome to error for variable

Im the repro, I am using a variable (timezone) before initialisation (error I saw at runtime was "ReferenceError: Cannot access 'timezone' before initialization"). Maybe I am misunderstanding how the rule works, but I do remember that eslint would mark these kinds of mistakes

Code of Conduct

• I agree to follow Biome's Code of Conduct

[Conaclos]

This is a particularly hard case to catch. TSC and ESLint doesn't report any issue either.

The issue comes from the execution of the promise before the declaration of a variable used in the callback.

[th1nkful]

A dev on my team pointed out that it's a different eslint rule that detects this - "no-use-before-define"

Is their similar in biome yet?

[Conaclos]

Is their similar in biome yet?

Yes it is noInvalidUseBeforeDeclaration.

Note that the ESLint rule reports false positives.
For instance, the following code should be valid:

const f = () => x;
const x = 0;
f();

Conversely, the Biome rule misses some cases.
We could try to improve it.