Suggestion: an option to make --showConfig more verbose

Search Terms

showConfig, verbose, verbosity

Suggestion

Currently, the --showConfig option will only print the compiler options that are provided by the given tsconfig.json.

The suggestion is to introduce another command line option to use together with --showConfig, for example --verbose, that would additionally print out the default values of all of the missing compiler options.

Use Cases

This new option hopes to make debugging configuration files easier by explicitly displaying the value of every compiler option.

Examples

Given the following folder structure:

.
├── main.ts
└── tsconfig.json

And the following tsconfig.json:

{
  "compilerOptions": {
    "target": "es5"
  },
  "include": ["**/*.ts"]
}

Running the command tsc --showConfig produces:

{
    "compilerOptions": {
        "target": "es5"
    },
    "files": [
        "./main.ts"
    ],
    "include": [
        "**/*.ts"
    ]
}

Here's an example output of tsc --showConfig --verbose. It was derived in the following way:

1. Use the Typescript Handbook's table of compiler options and their defaults as a reference.
2. Exclude deprecated options (out, reactNamespace, and skipDefaultLibCheck)
3. Also exclude any options that are missing a default value in the table, since JSON doesn't have a notion of undefined.

{
    "compilerOptions": {
        "allowJs": false,
        "allowSyntheticDefaultImports": false,
        "allowUmdGlobalAccess": false,
        "allowUnreachableCode": false,
        "allowUnusedLabels": false,
        "alwaysStrict": false,
        "build": false,
        "charset": "utf8",
        "checkJs": false,
        "composite": true,
        "declaration": false,
        "declarationMap": false,
        "diagnostics": false,
        "disableSizeLimit": false,
        "downlevelIteration": false,
        "emitBOM": false,
        "emitDeclarationOnly": false,
        "emitDecoratorMetadata": false,
        "esModuleInterop": false,
        "experimentalDecorators": false,
        "extendedDiagnostics": false,
        "forceConsistentCasingInFileNames": false,
        "importHelpers": false,
        "incremental": false,
        "inlineSourceMap": false,
        "inlineSources": false,
        "isolatedModules": false,
        "jsx": "preserve",
        "jsxFactory": "React.createElement",
        "keyofStringsOnly": false,
        "listEmittedFiles": false,
        "listFiles": false,
        "locale": "en", // [2]
        "module": "commonjs",
        "moduleResolution": "classic",
        "newLine": "lf", // [2]
        "noEmit": false,
        "noEmitHelpers": false,
        "noEmitOnError": false,
        "noErrorTruncation": false,
        "noFallthroughCasesInSwitch": false,
        "noImplicitAny": false,
        "noImplicitReturns": false,
        "noImplicitThis": false,
        "noImplicitUseStrict": false,
        "noLib": false,
        "noResolve": false,
        "noStrictGenericChecks": false,
        "noUnusedLocals": false,
        "noUnusedParameters": false,
        "preserveConstEnums": false,
        "preserveSymlinks": false,
        "preserveWatchOutput": false,
        "pretty": true, // [1]
        "removeComments": false,
        "resolveJsonModule": false,
        "rootDir": "(computed from the list of input files)", // [3]
        "showConfig": false,
        "skipLibCheck": false,
        "sourceMap": false,
        "strict": false,
        "strictBindCallApply": false,
        "strictFunctionTypes": false,
        "strictPropertyInitialization": false,
        "strictNullChecks": false,
        "suppressExcessPropertyErrors": false,
        "suppressImplicitAnyIndexErrors": false,
        "target": "es5",
        "traceResolution": false,
        "tsBuildInfoFile": ".tsbuildinfo"
    },
    "files": [
        "./main.ts"
    ],
    "include": [
        "**/*.ts"
    ]
}

^[1] The Handbook says pretty should be true unless piping or redirecting output to file, so the desired value here may be ambiguous?

^[2] locale and newLine are platform-specific.

^[3] rootDir would need to be calculated so it can be displayed.

Checklist

My suggestion meets these guidelines:

• This wouldn't be a breaking change in existing TypeScript/JavaScript code
• This wouldn't change the runtime behavior of existing JavaScript code
• This could be implemented without emitting different JS based on the types of the expressions
• This isn't a runtime feature (e.g. library functionality, non-ECMAScript syntax with JavaScript output, etc.)
• This feature would agree with the rest of TypeScript's Design Goals.

首先检查现有的 tsc --showConfig 行为，以及 issue 中引用的 Handbook 编译器选项默认值。定义 --verbose 应如何表示平台特定、计算得出、已弃用和未定义的选项；完成标准是该命令能够一致地显示预期的默认值，同时不改变普通 --showConfig 的输出。未指定源文件或测试。