feat: add reset function for observer

packages/core/package.json

@@ -26,11 +26,14 @@
     "@babel/code-frame": "7.14.5",
     "change-case": "4.1.2",
     "css-color-function": "1.3.3",
+    "deepcopy": "^2.1.0",
     "deepmerge": "4.2.2",
     "yaml": "1.10.2"
   },
   "devDependencies": {
     "@types/babel__code-frame": "7.0.3"
   },
-  "files": ["lib"]
+  "files": [
+    "lib"
+  ]
 }

packages/core/src/internal/__tests__/observer.test.ts

@@ -37,6 +37,25 @@ describe('ThemekitObserver', () => {
       ],
     })
   })
+
+  test('should reset tokens on reset', async () => {
+    const onWatch = jest.fn()
+    const compile = createCompiler(simple.context)
+    const observer = new ThemekitObserver(simple.options, compile)
+    observer.watch(onWatch)
+    observer.update('token1', 'value-1-updated')
+    observer.reset()
+    await wait(100)
+    expect(onWatch).toBeCalledTimes(3)
+    expect(onWatch).toHaveBeenLastCalledWith({
+      css: [
+        {
+          content: 'token1:value-1,token2:value-2',
+          destination: 'tokens.css',
+        },
+      ],
+    })
+  })
 })
 
 function wait(delay: number) {

packages/core/src/internal/observer.ts

@@ -1,18 +1,21 @@
 import { compile } from '../index'
 import { CompileResult, CompileOptions } from '../compiler'
-import { TokenValue } from '../types'
+import { RawToken, TokenValue } from '../types'
+import deepcopy from 'deepcopy'
 
 export type Watcher = (payload: CompileResult) => void
 type Compile = typeof compile
 
 export class ThemekitObserver {
+  private originalTokens: RawToken[]
   private options: CompileOptions
   private compile: Compile
   private watchers: Set<Watcher> = new Set()
 
   constructor(options: CompileOptions, _compile: Compile = compile) {
     this.compile = _compile
-    this.options = options
+    this.options = deepcopy(options)
+    this.originalTokens = deepcopy(options.tokens)
     this.run(options)
   }
 
@@ -29,6 +32,11 @@ export class ThemekitObserver {
     this.run(this.options)
   }
 
+  reset() {
+    this.options.tokens = deepcopy(this.originalTokens)
+    this.run(this.options)
+  }
+
   private run(options: CompileOptions) {
     setImmediate(() => {
       this.emit(this.compile(options))