Merge pull request #44 from rixo/fix-bindings

Fix bindings #43

.changeset/khaki-pets-exercise.md

@@ -0,0 +1,5 @@
+---
+'svelte-hmr': patch
+---
+
+Fix preserving bind: directive (fixes #43)

packages/svelte-hmr-spec/test/bindings.spec.js

@@ -56,8 +56,7 @@ describe('bindings', () => {
 
   `
 
-  // TODO should depend on preserveLocalState option
-  testHmr.skip`
+  testHmr`
     # resets bound values when owner is updated
 
     --- App.svelte ---
@@ -86,4 +85,257 @@ describe('bindings', () => {
       <input type="number" />
       <div>123</div>
   `
+
+  testHmr`
+    # instance function are preserved when binding to instance
+
+    --- App.svelte ---
+
+    <script>
+      import {onMount} from 'svelte'
+      import Foo from './Foo.svelte'
+
+      let foo
+      let x
+
+      const update = () => {
+        x = foo.get()
+      }
+
+      onMount(update)
+    </script>
+
+    <Foo bind:this={foo} />
+
+    <x-focus>{x}</x-focus>
+
+    <button on:click={update} />
+
+    --- Foo.svelte ---
+
+    <script>
+      ::0 export const get = () => 1
+      ::1 export const get = () => 2
+    </script>
+
+    * * * * *
+
+    ::0::
+      1
+    ::1::
+      ${clickButton()}
+      2
+  `
+
+  testHmr`
+    # const function bindings are preserved
+
+    --- App.svelte ---
+
+    <script>
+      import {onMount} from 'svelte'
+      import Foo from './Foo.svelte'
+
+      let get
+      let x
+
+      const update = () => {
+        x = get()
+      }
+
+      onMount(update)
+    </script>
+
+    <Foo bind:get />
+
+    <x-focus>{x}</x-focus>
+
+    <button on:click={update} />
+
+    --- Foo.svelte ---
+
+    <script>
+      ::0 export const get = () => 1
+      ::1 export const get = () => 2
+    </script>
+
+    * * * * *
+
+    ::0::
+      1
+    ::1::
+      ${clickButton()}
+      2
+  `
+
+  testHmr`
+    # const function bindings are preserved when variables change
+
+    --- App.svelte ---
+
+    <script>
+      import {onMount} from 'svelte'
+      import Foo from './Foo.svelte'
+
+      let get
+      let x
+
+      const update = () => {
+        x = get && get()
+      }
+
+      onMount(update)
+    </script>
+
+    <Foo bind:get />
+
+    <x-focus>{x}</x-focus>
+
+    <button on:click={update} />
+
+    --- Foo.svelte ---
+
+    <script>
+      ::0 export const get = () => 1
+
+      ::1 let foo = 'FOO'
+      ::1 export let bar = 'BAR'
+      ::1 export const get = () => 2
+      ::1 $: console.log(foo + bar)
+
+      ::2 let foo = 'FOO'
+      ::2 $: console.log(foo)
+      ::2 export const get = () => 3
+
+      ::3 export const set = () => {}
+
+      ::4 let foo = 'FOO'; let bar = 'BAR'; let baz = 'BAZ'; let bat = 'BAT';
+      ::4 $: console.log(foo + bar + baz + bat)
+      ::4 export const get = () => 4
+    </script>
+
+    * * * * *
+
+    ::0::
+      1
+    ::1:: exported function order in variables changes
+      1
+      ${clickButton()}
+      2
+    ::2:: exported function order in variables changes again
+      2
+      ${clickButton()}
+      3
+    ::3:: exported function disappears
+      3
+      ${clickButton()}
+      undefined
+    ::4:: exported function comes back (at another index)
+      undefined
+      ${clickButton()}
+      4
+  `
+
+  testHmr`
+    # let function bindings are preserved
+
+    --- App.svelte ---
+
+    <script>
+      import {onMount} from 'svelte'
+      import Foo from './Foo.svelte'
+
+      let get
+      let x
+
+      const update = () => {
+        x = get()
+      }
+
+      onMount(update)
+    </script>
+
+    <Foo bind:get />
+
+    <x-focus>{x}</x-focus>
+
+    <button id="update" on:click={update} />
+
+    --- Foo.svelte ---
+
+    <script>
+      ::0 export let get = () => 1
+      ::1 export let get = () => 2
+
+      export const change = () => {
+        get = () => 3
+      }
+    </script>
+
+    <button id="change-let" on:click={change} />
+
+    * * * * *
+
+    ::0::
+      1
+    ::1::
+      ${clickButton('#update')}
+      2
+      ${clickButton('#change-let')}
+      2
+      ${clickButton('#update')}
+      3
+  `
+
+  testHmr`
+    # binding to a prop that does not exists yet
+
+    --- App.svelte ---
+
+    <script>
+      import {onMount} from 'svelte'
+      import Foo from './Foo.svelte'
+
+      let get
+      let x
+
+      const update = () => {
+        x = get && get()
+      }
+
+      onMount(update)
+    </script>
+
+    <Foo bind:get />
+
+    <x-focus>{x}</x-focus>
+
+    <button on:click={update} />
+
+    --- Foo.svelte ---
+
+    <script>
+      ::0 export let bet = () => 1
+      ::1 export let get = () => 2
+      ::2 export let bet = () => 3
+      ::3 export let get = () => 4
+    </script>
+
+    * * * * *
+
+    ::0::
+      undefined
+    ::1::
+      undefined
+      ${clickButton()}
+      2
+    ::2:: doesn't reuse a wrong variable in the right place
+      2
+      ${clickButton()}
+      undefined
+    ::3:: remembers older future prop
+      undefined
+      ${clickButton()}
+      4
+  `
 })