Make Identifier.set_value work with inherited properties

packages/bind/src/bindingContext.ts

@@ -1,4 +1,4 @@
-import { extend, options, domData } from '@tko/utils'
+import { extend, options, domData, isObjectLike } from '@tko/utils'
 
 import {
     pureComputed
@@ -118,7 +118,7 @@ Object.assign(bindingContext.prototype, {
     }
     const $data = this.$data
     // instanceof Object covers 1. {}, 2. [], 3. function() {}, 4. new *;  it excludes undefined, null, primitives.
-    if ($data instanceof Object && token in $data) { return $data[token] }
+    if (isObjectLike($data) && token in $data) { return $data[token] }
     if (token in this) { return this[token] }
     if (token in globals) { return globals[token] }
 

packages/utils.parser/spec/identifierBehaviors.ts

@@ -32,7 +32,12 @@ import {
 describe('Identifier', function () {
   function testLookup (identifier, $data) {
     const ctx = new bindingContext($data)
-    return new Identifier(null, identifier).get_value(undefined, ctx)
+    return new Identifier(null, identifier).get_value(undefined, ctx, {})
+  }
+
+  function testWrite (identifier, $data, newValue) {
+    const ctx = new bindingContext($data)
+    return new Identifier(null, identifier).set_value(newValue, ctx, {})
   }
 
   var c = 'Z',
@@ -46,6 +51,12 @@ describe('Identifier', function () {
     assert.equal(testLookup('f', context), f)
   })
 
+  it('looks up values on no-prototype $data', function () {
+    const $data = Object.create(null)
+    $data.c = c
+    assert.equal(testLookup('c', $data), 'Z')
+  })
+
   it('returns null as expected', function () {
     assert.equal(testLookup('$data', null), null)
   })
@@ -54,6 +65,27 @@ describe('Identifier', function () {
     assert.equal(testLookup('$data', undefined), undefined)
   })
 
+  it('sets plain values on $data', () => {
+    const $data = { c: c }
+    assert.equal($data.c, 'Z')
+    testWrite('c', $data, 'X')
+    assert.equal($data.c, 'X')
+  })
+
+  it('sets observable values on $data', () => {
+    const $data = { c: observable(c) }
+    assert.equal($data.c(), 'Z')
+    testWrite('c', $data, 'X')
+    assert.equal($data.c(), 'X')
+  })
+
+  it('sets plain values on no-prototype $data', () => {
+    const $data = Object.create(null)
+    $data.c = c
+    testWrite('c', $data, 'X')
+    assert.equal($data.c, 'X')
+  })
+
   it('dereferences values on the parser', function () {
     var context = new bindingContext({ f: f })
     var fake_args = new Arguments(null, [])

packages/utils.parser/src/Identifier.ts

@@ -2,7 +2,7 @@
 import Node from './Node'
 import Arguments from './Arguments'
 
-import { hasOwnProperty } from '@tko/utils'
+import { hasOwnProperty, isObjectLike } from '@tko/utils'
 
 import {
   isWriteableObservable, isObservable
@@ -106,11 +106,11 @@ export default class Identifier {
     let leaf = this.token
     let i, n, root
 
-    if (hasOwnProperty($data, leaf)) {
+    if (isObjectLike($data) && leaf in $data) {
       root = $data
-    } else if (hasOwnProperty($context, leaf)) {
+    } else if (leaf in $context) {
       root = $context
-    } else if (hasOwnProperty(globals, leaf)) {
+    } else if (leaf in globals) {
       root = globals
     } else {
       throw new Error('Identifier::set_value -- ' +

packages/utils/src/object.ts

@@ -6,6 +6,10 @@ export function hasOwnProperty(obj, propName) {
   return Object.prototype.hasOwnProperty.call(obj, propName)
 }
 
+export function isObjectLike(obj) {
+  return !!obj && (typeof obj === 'object' || typeof obj === 'function')
+}
+
 export function extend (target, source) {
   if (source) {
     for (var prop in source) {