babel/packages/babel-plugin-transform-modules-commonjs/test/importInterop-function.js

import * as babel from "@babel/core";
import transformCommonjs from "../lib/index.js";
import externalHelpers from "@babel/plugin-external-helpers";
import path from "node:path";

describe("'importInterop'", () => {
  function transform(code, importInterop, filename) {
    return babel.transformSync(code, {
      configFile: false,
      filename,
      ast: false,
      plugins: [
        [externalHelpers, { helperVersion: "7.100.0" }],
        [transformCommonjs, { importInterop }],
      ],
    }).code;
  }

  it("'importInterop' accepts a function", () => {
    const code = `
      import a from "a";
      import b from "b";
      import c from "c";

      a();
      b();
      c();
    `;

    const importInterop = source => {
      if (source === "a") return "babel";
      else if (source === "b") return "node";
      else if (source === "c") return "none";
    };

    expect(transform(code, importInterop)).toMatchInlineSnapshot(`
      ""use strict";

      var _a = babelHelpers.interopRequireDefault(require("a"));
      var _b = require("b");
      var _c = require("c");
      (0, _a.default)();
      _b();
      (0, _c.default)();"
    `);
  });

  it("gets called with the filename if present", () => {
    const code = `
      import a from "a";
      import b from "b";
    `;

    const importInterop = jest.fn(() => "babel");

    const filename = "path/to/fake-filename.js";

    transform(code, importInterop, filename);

    expect(importInterop).toHaveBeenCalledTimes(2);
    expect(importInterop).toHaveBeenCalledWith("a", path.resolve(filename));
    expect(importInterop).toHaveBeenCalledWith("b", path.resolve(filename));
  });

  it("gets called with undefined if the filename is not present", () => {
    const code = `
      import a from "a";
      import b from "b";
    `;

    const importInterop = jest.fn(() => "babel");

    transform(code, importInterop);

    expect(importInterop).toHaveBeenCalledTimes(2);
    expect(importInterop).toHaveBeenCalledWith("a", undefined);
    expect(importInterop).toHaveBeenCalledWith("b", undefined);
  });
});