Remove tsconfig paths to relative imports

morph.ts

import * as path from "path";
import { Project } from "ts-morph";

function getRelativePath(fromPath: string, toPath: string): string {
  let relativePath = path.relative(path.dirname(fromPath), toPath);
  if (!relativePath.startsWith(".")) {
    relativePath = "./" + relativePath;
  }
  return relativePath.replace(/\\/g, "/");
}

function transformImports() {
  const project = new Project({
    tsConfigFilePath: "tsconfig.json",
  });

  const sourceFiles = project.getSourceFiles();
  const compilerOptions = project.getCompilerOptions();
  const paths = compilerOptions.paths || {};

  sourceFiles.forEach((sourceFile) => {
    let modified = false;
    const imports = sourceFile.getImportDeclarations();

    imports.forEach((importDecl) => {
      const moduleSpecifier = importDecl.getModuleSpecifierValue();

      for (const [alias, targets] of Object.entries(paths)) {
        const aliasPattern = alias.replace("/*", "");
        if (moduleSpecifier.startsWith(aliasPattern)) {
          const target = targets[0].replace("/*", "");
          const importPath = moduleSpecifier.replace(aliasPattern, target);
          const absolutePath = path.resolve(process.cwd(), importPath);
          const relativePath = getRelativePath(sourceFile.getFilePath(), absolutePath);

          importDecl.setModuleSpecifier(relativePath);
          modified = true;
        }
      }
    });

    if (modified) {
      sourceFile.save();
    }
  });
}

transformImports();