Typescript - How to compile only one (or more) files from a project using all the project settings from the tsconfig file(s)

custom-tsc.ts

import * as ts from 'typescript';
import * as fs from 'fs';
import * as path from 'path';
import * as cp from 'child_process';
import * as dm from '../src-ts/deep-merge-objects';
function compile(fileNames: string[], options: ts.CompilerOptions): void {
  const program = ts.createProgram(fileNames, options);
  const emitResult = program.emit();

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

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

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

function main(): void {
  fs.mkdirSync('./dev-out',{recursive:true})
  cp.execSync('cp -r ./testlib-js ./dev-out/');

  const tscfgFilenames = [
    '@tsconfig/node14/tsconfig.json',
    path.join(process.cwd(), 'tsconfig.base.json'),
    path.join(process.cwd(), 'tsconfig.json'),
  ];
  const tscfg = tscfgFilenames.map((fn) => require(fn).compilerOptions);
  const compilerOptions: ts.CompilerOptions = dm.deepMerge(
    dm.deepMergeInnerDedupeArrays,
    ...tscfg
  );

  if (compilerOptions.lib && compilerOptions.lib.length)
    compilerOptions.lib = compilerOptions.lib.map((s) => 'lib.' + s + '.d.ts');
  console.log(JSON.stringify(compilerOptions, null, 2));
  compile(process.argv.slice(2), compilerOptions);
}
try {
  main();
  if (process.exitCode === 1) console.log('compiler produced no output');
} catch (e) {
  console.error(e.message);
  process.exitCode = 2;
}

deep-merge-objects.ts

import * as ts from 'typescript';
import * as fs from 'fs';
import * as path from 'path';
import * as cp from 'child_process';
import * as dm from '../src-ts/deep-merge-objects';
function compile(fileNames: string[], options: ts.CompilerOptions): void {
  const program = ts.createProgram(fileNames, options);
  const emitResult = program.emit();

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

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

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

function main(): void {
  fs.mkdirSync('./dev-out',{recursive:true})
  cp.execSync('cp -r ./testlib-js ./dev-out/');

  const tscfgFilenames = [
    '@tsconfig/node14/tsconfig.json',
    path.join(process.cwd(), 'tsconfig.base.json'),
    path.join(process.cwd(), 'tsconfig.json'),
  ];
  const tscfg = tscfgFilenames.map((fn) => require(fn).compilerOptions);
  const compilerOptions: ts.CompilerOptions = dm.deepMerge(
    dm.deepMergeInnerDedupeArrays,
    ...tscfg
  );

  if (compilerOptions.lib && compilerOptions.lib.length)
    compilerOptions.lib = compilerOptions.lib.map((s) => 'lib.' + s + '.d.ts');
  console.log(JSON.stringify(compilerOptions, null, 2));
  compile(process.argv.slice(2), compilerOptions);
}
try {
  main();
  if (process.exitCode === 1) console.log('compiler produced no output');
} catch (e) {
  console.error(e.message);
  process.exitCode = 2;
}

tsconfig.xxx.json

{
  "compilerOptions": {
    "outDir": "dev-out",
    "rootDir": "./"
  },
}

Started off with the minimal compiler example

Had to add these items -

• Reading in the config file(s). That was not included in the original example.
• Merging the config files in order. (Not a problem if you use a single file).
• Transforming the compilerOptions.lib entries (e.g., es2020 => lib.es2020.d.ts)

Also note that is a good to have rootDir specified in a tsconfig. Otherwise it might not create the directory levels correctly.