jscodeshift transforms from import/export to require/module.exports for javascript

transform-default-import.sh

#!/bin/bash

jscodeshift -t transform-import-to-cjs.js --no-babel --parser=flow src/

transform-destructured-import-to-cjs.js

// Press ctrl+space for code completion
module.exports = function transformer(file, api) {
  const j = api.jscodeshift;

  return j(file.source)
    .find(j.ImportDeclaration)
    .forEach((path) => {
      const node = path.value;
      const specifiers = node.specifiers;
      const comments = node.comments;

      const destructuredImports = [];

      specifiers
        .filter((specifier) => specifier.type === "ImportSpecifier")
        .forEach((specifier) => {
          const importName = specifier.local.name;
          destructuredImports.push(importName);
          specifiers.splice(specifiers.indexOf(specifier), 1);
        });

      if (destructuredImports.length) {
        const requireDeclaration = j.variableDeclaration("const", [
          j.variableDeclarator(
            j.objectPattern(
              destructuredImports.map((name) => {
                const prop = j.objectProperty(
                  j.identifier(name),
                  j.identifier(name)
                );
                prop.shorthand = true;
                return prop;
              })
            ),
            j.callExpression(j.identifier("require"), [node.source])
          ),
        ]);

        // Comments are lost on the path.replace(), including file level comments for the first import.
        requireDeclaration.comments = comments;

        path.insertBefore(requireDeclaration);
      }

      if (specifiers.length == 0) {
        path.replace();
      }
    })
    .toSource();
};

transform-destructured-import.sh

#!/bin/bash

jscodeshift -t transform-destructured-import-to-cjs.js --no-babel --parser=flow src/

transform-export.sh

#!/bin/bash

find src -type f -name '*.js' -exec sed -i 's/^export default {/module.exports = {/g' {} +
find src -type f -name '*.js' -exec sed -i 's/^export default /module.exports = /g' {} +
find src -type f -name '*.js' -exec sed -i 's/^export {/module.exports = {/g' {} +

grep 'module.exports' -Ro src/ | sort | uniq -c | sort
echo "Fix any duplicate module.exports"

transform-import-to-cjs.js

/*
Converts
```
import myThing from "myLib";
```
to
```
const myThing = require("myLib");
```
*/

// TODO: avoid replacing if the import is both default and destructured:
// import myThing, { thingX, thingY } from "myLib";

// TODO: convert namespaced imports:
// import * as myThing from "myLib";

module.exports = function transformer(file, api) {
  const j = api.jscodeshift;

  return j(file.source)
    .find(j.ImportDeclaration)
    .forEach((path) => {
      const node = path.value;
      const specifiers = node.specifiers;
      const comments = node.comments;

      specifiers
        .filter((specifier) => specifier.type === "ImportDefaultSpecifier")
        .forEach((specifier) => {
          const importName = specifier.local.name;

          const requireDeclaration = j.variableDeclaration("const", [
            j.variableDeclarator(
              j.identifier(importName),
              j.callExpression(j.identifier("require"), [node.source])
            ),
          ]);
          requireDeclaration.comments = comments;
          path.replace(requireDeclaration);
        });
    })
    .toSource();
};