Reduce amount of code necessary to quickly format the diagnostics to a string

Search Terms

FormatDiagnosticsHost

Suggestion

Often when someone is working with the TypeScript compiler API their type checker might have diagnostics. It would be useful for people to quickly check them by typing:

ts.formatDiagnostics(ts.getPreEmitDiagnostics(program))

Instead of:

ts.formatDiagnostics(ts.getPreEmitDiagnostics(program), {
    getCurrentDirectory: () => ts.sys.getCurrentDirectory(),
    getCanonicalFileName: f => f,
    getNewLine: () => "\n"
})

Possible solution is to make providing FormatDiagnosticsHost optional or add a default FormatDiagnosticsHost that people can use (or both).

Also for ts.formatDiagnostic and ts.formatDiagnosticsWithColorAndContext

Use Cases

Easier for people to quickly check the diagnostics while they're developing with the compiler API.

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.

Related Issues

#29581

まず TypeScript コンパイラ API のエントリポイントである formatDiagnostics、formatDiagnostic、formatDiagnosticsWithColorAndContext から始め、現在 FormatDiagnosticsHost がどのように必須とされているかを追跡します。既存の呼び出しを維持しながら、提案されているオプションのホスト方式とデフォルトホスト方式を比較します。ホストを渡さずに diagnostics をすばやくフォーマットでき、既存の動作が変わらなければ完了です。