René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Potentially wrong 'showConfig' results for default values, as it's used in the checker differently.","articleBody":"### 🔎 Search Terms\r\n\r\n\"showConfig result moduleResolution wrong\"\r\n\r\n### 🕗 Version \u0026 Regression Information\r\n\r\n- This is the behavior in every version I tried, and I reviewed the FAQ for entries about showConfig\r\n\r\n\r\n### ⏯ Playground Link\r\n\r\n_No response_\r\n\r\n### 💻 Code\r\n\r\ntsconfig:\r\n```json\r\n{\r\n  \"compilerOptions\": {\r\n  }\r\n}\r\n```\r\n\r\ncli call:\r\n`tsc --showConfig`\r\n\r\n### 🙁 Actual behavior\r\n\r\n```json\r\n{    \r\n  \"compilerOptions\": {}\r\n}\r\n```\r\n\r\n\r\n### 🙂 Expected behavior\r\n\r\n### Wanted Output from `tsc --showConfig`\r\n\r\n```json\r\n{\r\n  \"compilerOptions\": {\r\n    \"moduleResolution\": \"Node10\",\r\n    // And All other fields which have default values\r\n  }\r\n}\r\n```\r\n\r\n### Explanation\r\nWhen we check utilities.ts: 8859 `computedOptions` we can see, that this moduleResolution has the following `computeValue` functionality and that its not the default value because it depends on the computed module value which is, if not set, `commonjs`. \r\n```typescript\r\n{\r\ndependencies: [\"module\", \"target\"],\r\n  computeValue: (compilerOptions): ModuleResolutionKind =\u003e {\r\n  let moduleResolution = compilerOptions.moduleResolution;\r\n  if (moduleResolution === undefined) {\r\n    switch (computedOptions.module.computeValue(compilerOptions)) {\r\n      case ModuleKind.CommonJS:\r\n        moduleResolution = ModuleResolutionKind.Node10;\r\n        break;\r\n      case ModuleKind.Node16:\r\n        moduleResolution = ModuleResolutionKind.Node16;\r\n        break;\r\n      case ModuleKind.NodeNext:\r\n        moduleResolution = ModuleResolutionKind.NodeNext;\r\n        break;\r\n      case ModuleKind.Preserve:\r\n        moduleResolution = ModuleResolutionKind.Bundler;\r\n        break;\r\n      default:\r\n        moduleResolution = ModuleResolutionKind.Classic;\r\n        break;\r\n    }\r\n  }\r\n  return moduleResolution;\r\n},\r\n    }\r\n```\r\n\r\nAnd in the compiler, it's used like this: \r\n```typescript\r\nexport const getEmitModuleResolutionKind = computedOptions.moduleResolution.computeValue;\r\n// Usage:\r\ngetEmitModuleResolutionKind(compilerOptions)\r\n```\r\n\r\nSo there is no checking for if the `dependencies` are used. So this means that the default value will be used even if there is no dependency specified in the tsconfig. \r\n\r\nBut in the showConfig code (commandLineParser.ts: 2565) we can see, that it checks if some of it's dependencies are there:\r\n```typescript\r\nif (!providedKeys.has(option) \u0026\u0026 some(computedOptions[option as keyof typeof computedOptions].dependencies, dep =\u003e providedKeys.has(dep))) {\r\n```\r\n\r\n### Suggestion \r\nSo I think the showConfig does not show the \"real\" values which are used during the execution of the code and I would suggest to change that to show all the properties if they have a value which is other than undefined. \r\n\r\n\r\n\r\n","author":{"url":"https://github.com/chwoerz","@type":"Person","name":"chwoerz"},"datePublished":"2024-07-27T08:09:18.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":9},"url":"https://github.com/59442/TypeScript/issues/59442"}