feat(data): add flagging of type=module (#386)

* feat(data): add flagging of type=module

I've looked around, and it seems like this is a sufficient heuristic to detect esm. I have explicitly left the most common case as unknown, so we can later find out which type those are.

References:
- https://nodejs.org/api/esm.html#esm_code_package_json_code_code_type_code_field
- https://github.com/rollup/rollup/wiki/pkg.module

There's also "jsnext:main", but that doesn't seem to be used anymore

* turn into array

* finish plural migration

README.md

@@ -121,6 +121,7 @@ For every single NPM package, we create a record in the Algolia index. The resul
     ts: 'definitely-typed', // definitely-typed | included | false
     definitelyTyped: '@types/babel__core',
   },
+  moduleTypes: ['unknown'], // esm | cjs | unknown
   humanDependents: '3.3k',
   changelogFilename: null, // if babel-core had a changelog, it would be the raw GitHub url here
   objectID: 'babel-core',

src/__tests__/__snapshots__/config.test.js.snap

@@ -96,6 +96,7 @@ Object {
       "searchable(owner.name)",
       "deprecated",
       "types.ts",
+      "moduleTypes",
     ],
     "customRanking": Array [
       "desc(_searchInternal.downloadsMagnitude)",

src/__tests__/__snapshots__/formatPkg.test.js.snap

@@ -46,6 +46,9 @@ Object {
   },
   "license": "Apache-2.0",
   "modified": 1510790341980,
+  "moduleTypes": Array [
+    "unknown",
+  ],
   "name": "@atlaskit/input",
   "objectID": "@atlaskit/input",
   "originalAuthor": undefined,
@@ -261,6 +264,9 @@ Object {
   },
   "license": "MIT",
   "modified": 1498153976616,
+  "moduleTypes": Array [
+    "unknown",
+  ],
   "name": "@atomic-package/tab",
   "objectID": "@atomic-package/tab",
   "originalAuthor": undefined,
@@ -383,6 +389,9 @@ Object {
   },
   "license": "MIT",
   "modified": 1554896045753,
+  "moduleTypes": Array [
+    "unknown",
+  ],
   "name": "create-instantsearch-app",
   "objectID": "create-instantsearch-app",
   "originalAuthor": undefined,
@@ -457,6 +466,9 @@ Object {
   "lastPublisher": null,
   "license": null,
   "modified": 1424001480609,
+  "moduleTypes": Array [
+    "unknown",
+  ],
   "name": "indexof",
   "objectID": "indexof",
   "originalAuthor": undefined,
@@ -540,6 +552,9 @@ Object {
   },
   "license": null,
   "modified": NaN,
+  "moduleTypes": Array [
+    "unknown",
+  ],
   "name": "long-boy",
   "objectID": "long-boy",
   "originalAuthor": undefined,

src/__tests__/formatPkg.test.js

@@ -1,5 +1,6 @@
 import formatPkg from '../formatPkg.js';
 import rawPackages from './rawPackages.json';
+import preact from './preact-simplified.json';
 import isISO8601 from 'validator/lib/isISO8601.js';
 
 it('transforms correctly', () => {
@@ -441,3 +442,68 @@ describe('alternative names', () => {
     `);
   });
 });
+
+describe('moduleTypes', () => {
+  test('type=module', () => {
+    expect(
+      formatPkg({
+        name: 'irrelevant',
+        lastPublisher: { name: 'unknown' },
+        type: 'module',
+      }).moduleTypes
+    ).toEqual(['esm']);
+  });
+
+  test('type=commonjs', () => {
+    expect(
+      formatPkg({
+        name: 'irrelevant',
+        lastPublisher: { name: 'unknown' },
+        type: 'commonjs',
+      }).moduleTypes
+    ).toEqual(['cjs']);
+  });
+
+  test('module=xxx.js', () => {
+    expect(
+      formatPkg({
+        name: 'irrelevant',
+        lastPublisher: { name: 'unknown' },
+        module: 'index.js',
+      }).moduleTypes
+    ).toEqual(['esm']);
+  });
+
+  test('main: index.mjs', () => {
+    expect(
+      formatPkg({
+        name: 'irrelevant',
+        lastPublisher: { name: 'unknown' },
+        main: 'index.mjs',
+      }).moduleTypes
+    ).toEqual(['esm']);
+  });
+
+  test('main: index.cjs', () => {
+    expect(
+      formatPkg({
+        name: 'irrelevant',
+        lastPublisher: { name: 'unknown' },
+        main: 'index.cjs',
+      }).moduleTypes
+    ).toEqual(['cjs']);
+  });
+
+  test('unknown', () => {
+    expect(
+      formatPkg({
+        name: 'irrelevant',
+        lastPublisher: { name: 'unknown' },
+      }).moduleTypes
+    ).toEqual(['unknown']);
+  });
+
+  test('preact (esm & umd)', () => {
+    expect(formatPkg(preact).moduleTypes).toEqual(['esm']);
+  });
+});