jscodeshift script to replace an import with another. should be called like `find $1 -iname '*.tsx' -print | xargs ./node_modules/.bin/jscodeshift -t import-replacer.ts -fromModule react-apollo -fromImport graphql -toModule @apollo/client -toImport graphql`

import-replacer.tsx

/* tslint:disable */
// @ts-nocheck
/*
 * This codemod can replace imports
 * for exmalple it can change
 * import {compose} from 'react-apollo'
 * into
 * import {flowRight as compose} from 'lodash'
 *
Should be called like:

find $1 -iname '*.tsx' -print | xargs ./node_modules/.bin/jscodeshift -t import-replacer.ts -fromModule react-apollo -fromImport graphql -toModule @apollo/client -toImport graphql

 * */

import { Transform } from "jscodeshift";
import { ImportDeclaration, JSCodeshift } from "jscodeshift";
import { ImportDeclarationBuilder } from "ast-types/gen/builders";


const codeContainsImport = (
  j: JSCodeshift,
  source: string,
  options: { [key: string]: string }
) => {
  return (
    j(source)
      .find<ImportDeclaration>(j.ImportDeclaration)
      .filter(imp => {
        const importLine = imp.node;
        return importLine.source.value === options.fromModule;
      })
      .filter(imp => {
        return imp.node.specifiers.some(
          s => s.imported && s.imported.name === options.fromImport
        );
      }).length > 0
  );
};

const containsReplacer = (
  j: JSCodeshift,
  source: string,
  options: { [key: string]: string }
) => {
  return (
    j(source)
      .find<ImportDeclaration>(j.ImportDeclaration)
      .filter(imp => {
        const importLine = imp.node;
        return importLine.source.value === options.toModule;
      }).length > 0
  );
};

const transform: Transform = (fileInfo, api, options) => {
  const { fromModule, fromImport, toModule, toImport } = options;
  if (![fromModule, fromImport, toModule, toImport].every(i => i)) {
    throw new Error(
      "Didn't receive all the arguments: fromModule, fromImport, toModule, toImport"
    );
  }

  const j = api.jscodeshift;
  const importDeclaration: ImportDeclarationBuilder = j.importDeclaration as any;

  // does the current file contains a reference to import of compose from react-apollo?
  const hasFromImport = codeContainsImport(j, fileInfo.source, options);
  if (!hasFromImport) {
    return;
  }
  // remove instances of compose from react-apollo import
  const sourceAfterRemovingSourceImport = j(fileInfo.source)
    .find<ImportDeclaration>(j.ImportDeclaration)

    .filter(imp => {
      const importLine = imp.node;
      return importLine.source.value === options.fromModule;
    })

    .replaceWith(p => {
      const specifiers = p.node.specifiers.filter(
        s =>
          s.type === "ImportDefaultSpecifier" ||
          (s.imported && s.imported.name !== options.fromImport)
      );

      if (!specifiers.length) return;

      return importDeclaration(specifiers, {
        value: options.fromModule,
        type: "Literal"
      });
    })
    .toSource();

  const replacerSpecifier = {
    imported: {
      name: options.toImport,
      type: "Identifier"
    },
    type: "ImportSpecifier"
  };

  const importFromReplacer = importDeclaration([replacerSpecifier], {
    value: options.toModule,
    type: "Literal"
  });

  const hasReplacer = containsReplacer(j, sourceAfterRemovingSourceImport, options);
  // do we already have an import from microscopekit in this file? them add a new import statement for microscopekit
  if (!hasReplacer) {
    const decl = j(sourceAfterRemovingSourceImport)
      .find<ImportDeclaration>(j.ImportDeclaration)
      .at(0)
      .insertAfter(importFromReplacer);

    return decl.toSource();
  }
  // otherwise amend a compose to the existing one
  const decl = j(sourceAfterRemovingSourceImport)
    .find<ImportDeclaration>(j.ImportDeclaration, node => {
      return node.source.value === options.toModule;
    })
    .at(0)

    .replaceWith(p => {
      return importDeclaration(
        [...(p.node.specifiers as any), replacerSpecifier],
        {
          value: options.toModule,
          type: "Literal"
        }
      );
    });
  return decl.toSource();
};

export const parser = "tsx";

export default transform;