ts-mini-compiler.ts

import * as ts from "typescript";

const getLineTextFromFilePosition = (
  file: ts.SourceFile,
  { line, character }: ts.LineAndCharacter,
): string => {
  const lines = file.getFullText().split("\n");
  return lines[line]?.slice(character) ?? "";
};

function compile(fileNames: string[], options: ts.CompilerOptions): void {
  let program = ts.createProgram(fileNames, options);
  let emitResult = program.emit();

  let allDiagnostics = ts
    .getPreEmitDiagnostics(program)
    .concat(emitResult.diagnostics);

  allDiagnostics.forEach((diagnostic) => {
    if (diagnostic.file) {
      let { line, character } = ts.getLineAndCharacterOfPosition(
        diagnostic.file,
        diagnostic.start!,
      );
      let message = ts.flattenDiagnosticMessageText(
        diagnostic.messageText,
        "\n",
      );
      const lineText = getLineTextFromFilePosition(diagnostic.file, {
        line,
        character,
      });
      console.log(
        `${diagnostic.file.fileName} (${line + 1},${character + 1}): ${message}
        
----
${lineText}
----`,
      );
    } else {
      console.log(
        ts.flattenDiagnosticMessageText(diagnostic.messageText, "\n"),
      );
    }
  });

  let exitCode = emitResult.emitSkipped ? 1 : 0;
  console.log(`Process exiting with code '${exitCode}'.`);
  process.exit(exitCode);
}

const tsconfig = ts.readConfigFile("tsconfig.json", ts.sys.readFile);
const config = ts.parseJsonConfigFileContent(tsconfig.config, ts.sys, "./");
compile(config.fileNames, config.options);