feat: Add outLodashPackage feature to allow for lodash-es, fix .cjs and .mjs files. (#2)

* feat: add outLodashPackage feature to allow for lodash-es

* fix: Fix loader for cjs and mjs extension files

Author: mbullington

README.md

@@ -62,4 +62,7 @@ isEmpty(something);
 
 ## Options
 
-You can specify your own `filter` as per according to esbuild docs [here](https://esbuild.github.io/plugins/#concepts).
+You can specify your own `filter` as per according to esbuild docs [here](https://esbuild.github.io/plugins/#concepts).
+
+You can specify `outLodashPackage` which by default is `lodash`. An example
+of this would be specifying calls to be rewritten to use `lodash-es`.

__tests__/fixtures/es/input.mjs

@@ -0,0 +1,11 @@
+import { isEmpty, chunk } from 'lodash';
+
+const empty = {};
+const notEmpty = {
+  a: 1,
+};
+
+checkIsEmpty(obj);
+checkIsEmpty(notEmpty);
+
+chunk(['a', 'b', 'c', 'd'], 2);

__tests__/fixtures/es/output.js

@@ -0,0 +1,9 @@
+import isEmpty from "lodash-es/isEmpty";
+import chunk from "lodash-es/chunk";
+const empty = {};
+const notEmpty = {
+  a: 1
+};
+checkIsEmpty(obj);
+checkIsEmpty(notEmpty);
+chunk(["a", "b", "c", "d"], 2);

__tests__/index.test.js

@@ -22,6 +22,19 @@ describe('Lodash plugin tests', () => {
     expect(res.outputFiles[0].text).toStrictEqual(output);
   });
 
+  it('should honor outLodashPackage option', async () => {
+    const output = fs.readFileSync(resolvePath('fixtures/es/output.js'), 'utf-8');
+
+    const res = await esbuild.build({
+      entryPoints: [resolvePath('fixtures/es/input.mjs')],
+      bundle: false,
+      plugins: [lodashPlugin({ outLodashPackage: 'lodash-es' })],
+      write: false,
+    });
+
+    expect(res.outputFiles[0].text).toStrictEqual(output);
+  });
+
   it('should handle destructured import transformation', async () => {
     const output = fs.readFileSync(resolvePath('fixtures/destructured/output.js'), 'utf-8');
 

index.js

@@ -1,16 +1,19 @@
 const fs = require('fs');
 const path = require('path');
 
+// All extensions included here: https://esbuild.github.io/content-types/#javascript
+const JS_EXTENSIONS = new Set(['js', 'cjs', 'mjs']);
+
 function pluginLodashImport(options = {}) {
-  const { filter = /.*/ } = options;
+  const { filter = /.*/, outLodashPackage = 'lodash' } = options;
 
   return {
     name: 'lodash',
     setup(build) {
       build.onLoad({ filter }, async args => {
         const contents = await fs.promises.readFile(args.path, 'utf8');
         const extension = path.extname(args.path).replace('.', '');
-        const loader = extension === 'js' ? 'jsx' : extension;
+        const loader = JS_EXTENSIONS.has(extension) ? 'jsx' : extension;
 
         const lodashImportRegex = /import\s+?(?:(?:(?:[\w*\s{},]*)\s+from\s+?)|)(?:(?:'lodash\/?.*?'))[\s]*?(?:;|$|)/g;
 
@@ -49,9 +52,9 @@ function pluginLodashImport(options = {}) {
             const previousResult = `${result ? `${result}\n` : ''}`;
             if (name.includes(' as ')) {
               const [realName, alias] = name.split(' as ');
-              result = `${previousResult}import ${alias} from 'lodash/${realName}';`;
+              result = `${previousResult}import ${alias} from '${outLodashPackage}/${realName}';`;
             } else {
-              result = `${previousResult}import ${name} from 'lodash/${name}';`;
+              result = `${previousResult}import ${name} from '${outLodashPackage}/${name}';`;
             }
           });