feat(vModel): handle true-value and false-value for checkbox (#449)

packages/runtime-dom/src/patchProp.ts

@@ -5,9 +5,9 @@ import { patchDOMProp } from './modules/props'
 import { patchEvent } from './modules/events'
 import { isOn } from '@vue/shared'
 import {
-  VNode,
   ComponentInternalInstance,
-  SuspenseBoundary
+  SuspenseBoundary,
+  VNode
 } from '@vue/runtime-core'
 
 export function patchProp(
@@ -53,6 +53,15 @@ export function patchProp(
           unmountChildren
         )
       } else {
+        // special case for <input v-model type="checkbox"> with
+        // :true-value & :false-value
+        // store value as dom properties since non-string values will be
+        // stringified.
+        if (key === 'true-value') {
+          ;(el as any)._trueValue = nextValue
+        } else if (key === 'false-value') {
+          ;(el as any)._falseValue = nextValue
+        }
         patchAttr(el, key, nextValue)
       }
       break