Remove symbol-observable and loose-envify deps

.github/workflows/size.yaml

@@ -14,4 +14,4 @@ jobs:
       - uses: preactjs/compressed-size-action@v1
         with:
           repo-token: '${{ secrets.GITHUB_TOKEN }}'
-          pattern: './{dist,es,lib}/*.js'
+          pattern: './{dist,es,lib}/*.{js,mjs}'

index.d.ts

@@ -1,5 +1,3 @@
-/// <reference types="symbol-observable" />
-
 /**
  * An *action* is a plain object that represents an intention to change the
  * state. Actions are the only way to get data into the store. Any data,
@@ -224,6 +222,12 @@ export interface Unsubscribe {
   (): void
 }
 
+declare global {
+  interface SymbolConstructor {
+    readonly observable: symbol
+  }
+}
+
 /**
  * A minimal observable of state changes.
  * For more information, see the observable proposal:

package.json

@@ -49,8 +49,6 @@
     "examples:test": "cross-env CI=true babel-node examples/testAll.js"
   },
   "dependencies": {
-    "loose-envify": "^1.4.0",
-    "symbol-observable": "^2.0.3",
     "@babel/runtime": "^7.9.2"
   },
   "devDependencies": {
@@ -102,11 +100,6 @@
       ]
     }
   ],
-  "browserify": {
-    "transform": [
-      "loose-envify"
-    ]
-  },
   "jest": {
     "testRegex": "(/test/.*\\.spec\\.[tj]s)$",
     "coverageProvider": "v8"

src/createStore.js

@@ -1,4 +1,4 @@
-import $$observable from 'symbol-observable'
+import $$observable from './utils/symbol-observable'
 
 import ActionTypes from './utils/actionTypes'
 import isPlainObject from './utils/isPlainObject'

src/utils/symbol-observable.js

@@ -0,0 +1,3 @@
+// Inlined version of the `symbol-observable` polyfill
+export default (() =>
+  (typeof Symbol === 'function' && Symbol.observable) || '@@observable')()

test/createStore.spec.js

@@ -11,12 +11,15 @@ import {
 import * as reducers from './helpers/reducers'
 import { from } from 'rxjs'
 import { map } from 'rxjs/operators'
-import $$observable from 'symbol-observable'
+import $$observable from '../src/utils/symbol-observable'
 
 describe('createStore', () => {
   it('exposes the public API', () => {
     const store = createStore(combineReducers(reducers))
-    const methods = Object.keys(store)
+
+    // Since switching to internal Symbol.observable impl, it will show up as a key in node env
+    // So we filter it out
+    const methods = Object.keys(store).filter((key) => key !== $$observable)
 
     expect(methods.length).toBe(4)
     expect(methods).toContain('subscribe')

test/typescript/store.ts

@@ -9,7 +9,8 @@ import {
   Unsubscribe,
   Observer,
 } from 'redux'
-import 'symbol-observable'
+// @ts-ignore
+import $$observable from '../src/utils/symbol-observable'
 
 type BrandedString = string & { _brand: 'type' }
 const brandedString = 'a string' as BrandedString