feat(action.type): remove Symbol from allowed types (#86)

BREAKING: `type` now *must* be a string constant.

Resolves #39.
Resolves #9.

Author: unional

README.md

@@ -62,7 +62,7 @@ An action MUST NOT include properties other than `type`, `payload`, `error`, and
 
 ### `type`
 
-The `type` of an action identifies to the consumer the nature of the action that has occurred. By convention, `type` is usually a string constant or a Symbol. If two types are the same, they MUST be strictly equivalent (using `===`).
+The `type` of an action identifies to the consumer the nature of the action that has occurred. `type` is a string constant. If two types are the same, they MUST be strictly equivalent (using `===`).
 
 ### `payload`
 

src/index.d.ts

@@ -3,7 +3,7 @@ export interface FluxStandardAction<Payload, Meta> {
    * The `type` of an action identifies to the consumer the nature of the action that has occurred.
    * Two actions with the same `type` MUST be strictly equivalent (using `===`)
    */
-  type: string | symbol;
+  type: string;
   /**
    * The optional `payload` property MAY be any type of value.
    * It represents the payload of the action.

src/index.js

@@ -1,13 +1,12 @@
 import {
   isPlainObject,
   isString,
-  isSymbol,
 } from 'lodash';
 
 export function isFSA(action) {
   return (
     isPlainObject(action) &&
-    (isString(action.type) || isSymbol(action.type)) &&
+    isString(action.type) &&
     Object.keys(action).every(isValidKey)
   );
 }

test/isFSA.test.js

@@ -1,7 +1,6 @@
 import { isFSA } from '../src/';
 
 const type = 'ACTION_TYPE';
-const symbolType = Symbol.for(type);
 
 describe('isFSA()', () => {
   it('requires a type', () => {
@@ -17,9 +16,7 @@ describe('isFSA()', () => {
     expect(isFSA(action)).toBe(false);
   });
 
-  it('only returns true if type is a string or symbol', () => {
-    // remove this assertion if/when symbol support is dropped
-    expect(isFSA({ type: symbolType })).toBe(true);
+  it('only returns true if type is a string', () => {
     expect(isFSA({ type: true })).toBe(false);
     expect(isFSA({ type: 123 })).toBe(false);
   });