Merge pull request #9 from alanblins/custom-merge

feat: add custom merge option

README.md

@@ -56,5 +56,33 @@ Type: `string`
 
 JSON output destination.
 
+### merge
+
+Type: `(items: JSONValue[]) => JSONValue`
+
+By default the merge function uses `Object.assign`.
+
+```js
+const esbuild = require('esbuild');
+const jsonMerge = require('esbuild-plugin-json-merge');
+const { defaultComposer } = require('default-composer');
+
+const { version, name, description } = require('./package.json');
+
+esbuild
+  .build({
+    entryPoints: ['src/index.js'],
+    outdir: 'build',
+    plugins: [
+      jsonMerge({
+        entryPoints: ['src/manifest.json', { version, name, description }],
+        outfile: 'manifest.json',
+        merge: (items) => defaultComposer(...items), //Custom merge
+      }),
+    ],
+  })
+  .catch(() => process.exit(1));
+```
+
 [package-version-badge]: https://badge.fury.io/js/esbuild-plugin-json-merge.svg
 [package-version]: https://www.npmjs.com/package/esbuild-plugin-json-merge

__tests__/__fixtures__/listobjects/a.json

@@ -0,0 +1,14 @@
+{
+  "name": "Aral 😊",
+  "surname": "",
+  "isDeveloper": true,
+  "isDesigner": false,
+  "age": 33,
+  "address": {
+    "street": "123 Main St",
+    "city": "Anytown",
+    "state": "CA"
+  },
+  "emails": ["contact@aralroca.com"],
+  "hobbies": ["programming"]
+}

__tests__/__fixtures__/listobjects/b.json

@@ -0,0 +1,10 @@
+{
+  "name": "Aral",
+  "emails": [],
+  "phone": "555555555",
+  "age": null,
+  "address": {
+    "zip": "54321"
+  },
+  "hobbies": ["parkour", "computer science", "books", "nature"]
+}

__tests__/index.test.js

@@ -1,6 +1,7 @@
 const os = require('os');
 const path = require('path');
 
+const { defaultComposer } = require('default-composer');
 const { build } = require('esbuild');
 const fse = require('fs-extra');
 
@@ -52,3 +53,27 @@ it('should merge list files', async () => {
   });
   expect(json).toEqual([null, 1, false, 4, 5]);
 });
+
+it('should merge list files with custom merge', async () => {
+  const json = await merge({
+    entryPoints: [path.join(FIXTURES_DIR, 'listobjects/*.json')],
+    outfile: 'out.json',
+    merge: (items) => defaultComposer(...items),
+  });
+  expect(json).toEqual({
+    name: 'Aral',
+    surname: '',
+    isDeveloper: true,
+    isDesigner: false,
+    emails: ['contact@aralroca.com'],
+    phone: '555555555',
+    age: 33,
+    address: {
+      street: '123 Main St',
+      city: 'Anytown',
+      state: 'CA',
+      zip: '54321',
+    },
+    hobbies: ['parkour', 'computer science', 'books', 'nature'],
+  });
+});

package.json

@@ -52,6 +52,7 @@
     "@types/jest": "^29.2.6",
     "@types/node": "^18.11.18",
     "cz-conventional-changelog": "^3.3.0",
+    "default-composer": "^0.6.0",
     "esbuild": "^0.17.4",
     "eslint": "^8.32.0",
     "husky": "^8.0.3",

src/index.ts

@@ -26,12 +26,16 @@ const getContentChunks = (entryPoints: InputEntry[]): Promise<JSONValue[]> =>
       ),
   ).then((items) => items.flat().filter((item) => item != null));
 
-const merge = (items: JSONValue[]): JSONValue =>
+const defaultMerge = (items: JSONValue[]): JSONValue =>
   // eslint-disable-next-line @typescript-eslint/ban-ts-comment
   // @ts-ignore
   Object.assign(...items);
 
-export = ({ entryPoints, outfile }: Options = {}): Plugin => ({
+export = ({
+  entryPoints,
+  outfile,
+  merge = defaultMerge,
+}: Options = {}): Plugin => ({
   name: NAME,
   async setup(build) {
     if (!outfile) {

src/interface.ts

@@ -11,4 +11,5 @@ export type InputEntry = string | JSONValue[] | { [key: string]: JSONValue };
 export type Options = Partial<{
   entryPoints: InputEntry[];
   outfile: string;
+  merge?: (items: JSONValue[]) => JSONValue;
 }>;