jscodeshift transform script used to rewrite import statements to fix incompatibility with nodejs native ES module loader

README.md

transform-add-ext-to-local-imported-modules.cjs is a small jscodeshift transformer which rewrites relative paths in the static import statements to fix an incompatibility with the nodejs native ES module loader (which requires a file extension for imports using related paths).

npx jscodeshift --parser=babylon -t transform-add-ext-to-local-imported-modules.cjs tests/functional/test.typo.run.js

transform-add-ext-to-local-imported-modules.cjs

/**
 * This adds .js to all imports related to local modules.
 */
module.exports = function(fileInfo, api /*, options */) {
  // console.log("CANARY transform called", api.jscodeshift(fileInfo.source).__paths[0].value.program.body, api.ImportDeclaration);
  return api.jscodeshift(fileInfo.source)
    .find("ImportDeclaration")
    .filter((p) => {
      return (
        p.value.source.type === 'StringLiteral' &&
        p.value.importKind !== 'type' &&
        p.value.source.value?.startsWith('.') &&
        (
          !p.value.source.value?.endsWith('.js') ||
          p.value.source.value?.includes('/src/')
        )
      );
    })
    .replaceWith((p) => {
      if (p.value.source.value.includes('/src/')) {
        p.value.source.value = p.value.source.value.replace(
          '/src/',
          '/lib/'
        );
      }

      if (!p.value.source.value.endsWith('.js')) {
        const {statSync} = require('fs');
        const path = require('path');
        let isDirectory = false;

        try {
          isDirectory = statSync(
            path.resolve(path.dirname(fileInfo.path), p.value.source.value)
          ).isDirectory();
        } catch (err) {
          // statSync throws if the directory doesn't exist (e.g. because
          // the import is actually meant to point to a file).
        }
        
        const newValue = isDirectory
          ? `${p.value.source.value}/index.js`
          : `${p.value.source.value}.js`;
        p.value.source.value = newValue;
      }

      console.log("Rewrote import to", p.value.source.value);
      return p.value;
    })
    .toSource({ quote: 'single' });
};