feat(proxy-state-tree): pass information on mutation on how to revert

Author: christianalfoni

packages/node_modules/proxy-state-tree/src/Proxyfier.ts

@@ -21,6 +21,35 @@ const arrayMutations = new Set([
 const getValue = (proxyOrValue) =>
   proxyOrValue && proxyOrValue[IS_PROXY] ? proxyOrValue[VALUE] : proxyOrValue
 
+const getArrayRevertValue = (method: string, target: any[], args: any[]) => {
+  switch (method) {
+    case 'push': {
+      return null
+    }
+    case 'shift': {
+      return target[0]
+    }
+    case 'pop': {
+      return target[target.length - 1]
+    }
+    case 'unshift': {
+      return null
+    }
+    case 'splice': {
+      return target.slice(args[0], args[1])
+    }
+    case 'reverse': {
+      return null
+    }
+    case 'sort': {
+      return null
+    }
+    case 'copyWithin': {
+      return null
+    }
+  }
+}
+
 export class Proxifier {
   CACHED_PROXY = Symbol('CACHED_PROXY')
   constructor(private tree: TTree) {}
@@ -145,6 +174,7 @@ export class Proxifier {
               path: path,
               args: args,
               hasChangedValue: true,
+              revertValue: getArrayRevertValue(method, target, args),
             })
 
             if (process.env.NODE_ENV === 'production') {
@@ -277,6 +307,7 @@ export class Proxifier {
             path: nestedPath,
             args: [value],
             hasChangedValue: value !== target[prop],
+            revertValue: target[prop],
           },
           objectChangePath
         )

packages/node_modules/proxy-state-tree/src/index.test.ts

@@ -60,6 +60,7 @@ describe('TrackStateAccessTree', () => {
         path: 'foo',
         args: ['bar2'],
         hasChangedValue: true,
+        revertValue: 'bar',
       })
     })
 
@@ -203,6 +204,7 @@ describe('OBJECTS', () => {
           path: 'foo',
           args: ['bar'],
           hasChangedValue: false,
+          revertValue: 'bar',
         },
       ])
       expect(renderCount).toBe(0)
@@ -220,6 +222,7 @@ describe('OBJECTS', () => {
           path: 'foo',
           args: ['bar2'],
           hasChangedValue: true,
+          revertValue: 'bar',
         },
       ])
       expect(mutationTree.state.foo).toBe('bar2')
@@ -420,6 +423,7 @@ describe('ARRAYS', () => {
           path: 'foo',
           args: ['bar'],
           hasChangedValue: true,
+          revertValue: null,
         },
       ])
 
@@ -439,13 +443,14 @@ describe('ARRAYS', () => {
           path: 'foo',
           args: [],
           hasChangedValue: true,
+          revertValue: 'foo',
         },
       ])
 
       expect(state.foo.length).toBe(0)
     })
 
-    test('should track POP mutations', () => {
+    test('should track SHIFT mutations', () => {
       const state = {
         foo: ['foo'],
       }
@@ -459,6 +464,7 @@ describe('ARRAYS', () => {
           path: 'foo',
           args: [],
           hasChangedValue: true,
+          revertValue: 'foo',
         },
       ])
 
@@ -478,6 +484,7 @@ describe('ARRAYS', () => {
           path: 'foo',
           args: ['foo'],
           hasChangedValue: true,
+          revertValue: null,
         },
       ])
 
@@ -497,6 +504,7 @@ describe('ARRAYS', () => {
           path: 'foo',
           args: [0, 1, 'bar'],
           hasChangedValue: true,
+          revertValue: ['foo'],
         },
       ])
 
@@ -639,6 +647,7 @@ describe('REACTIONS', () => {
         path: 'foo',
         args: ['bar2'],
         hasChangedValue: true,
+        revertValue: 'bar',
       })
     })
 
@@ -745,12 +754,14 @@ describe('REACTIONS', () => {
           method: 'set',
           args: ['bar2'],
           hasChangedValue: true,
+          revertValue: 'bar',
         },
         {
           path: 'foo',
           method: 'set',
           args: ['bar3'],
           hasChangedValue: true,
+          revertValue: 'bar2',
         },
       ],
     })

packages/node_modules/proxy-state-tree/src/types.ts

@@ -8,6 +8,7 @@ export interface IMutation {
   path: string
   args: any[]
   hasChangedValue: boolean
+  revertValue?: any
 }
 
 export interface IMutationCallback {