A jscodeshift codemod for converting any Lodash imports into direct imports

lodash-imports-codemod.js

export default (fileInfo, api) => {
  const j = api.jscodeshift;
  const root = j(fileInfo.source);
  let specifiers = [];

  root
    .find(j.ImportDeclaration, isLodashImport)
    .forEach((path) => specifiers.push(...path.node.specifiers.map((specifier) => specifier.local.name)))
    .remove();

  root
    .find(j.CallExpression, isLodashExpression)
    .forEach((path) => specifiers.push(path.node.callee.property.name))
    .replaceWith((path) => replaceExpression(path, j));

  if (specifiers.length) {
    cleanSpecifiers(specifiers).forEach((specifier) => {
      root.find(j.Declaration).at(0).get()
        .insertBefore(createImport(j, specifier));
    });
  }

  return root.toSource();
};

function isLodashImport (node) {
  return node.source.value.startsWith('lodash');
}

function isLodashExpression (node) {
  return node.callee.type === 'MemberExpression' && node.callee.object && node.callee.object.name === '_';
}

function replaceExpression (path, j) {
  return j.callExpression(j.identifier(path.node.callee.property.name), path.node.arguments);
}

function cleanSpecifiers (specifiers) {
  return specifiers.filter((specifier, i) => {
    return specifier !== '_' && specifiers.indexOf(specifier) === i;
  });
}

function createImport (j, specifier) {
  return j.importDeclaration(
    [j.importDefaultSpecifier(j.identifier(specifier))],
    j.stringLiteral(`lodash/${specifier}`)
  );
}