From 0b64040a9ff17b17a761c7b26bd822806ef1e5c9 Mon Sep 17 00:00:00 2001
From: Lachlan Miller <lachlan.miller.1990@outlook.com>
Date: Sat, 11 Apr 2020 16:31:06 +1000
Subject: [PATCH] feat: setData

---
 package.json          |  4 +++
 src/vue-wrapper.ts    | 10 ++++++-
 tests/setData.spec.ts | 67 +++++++++++++++++++++++++++++++++++++++++++
 yarn.lock             |  5 ++++
 4 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 tests/setData.spec.ts

diff --git a/package.json b/package.json
index 779969fbc..aaaa1bcc9 100644
--- a/package.json
+++ b/package.json
@@ -56,5 +56,9 @@
     "*.ts": [
       "prettier --parser=typescript --write"
     ]
+  },
+  "dependencies": {
+    "@types/lodash": "^4.14.149",
+    "lodash": "^4.17.15"
   }
 }
diff --git a/src/vue-wrapper.ts b/src/vue-wrapper.ts
index 93f99ff03..cdae6c634 100644
--- a/src/vue-wrapper.ts
+++ b/src/vue-wrapper.ts
@@ -1,5 +1,6 @@
-import { ComponentPublicInstance } from 'vue'
+import { ComponentPublicInstance, nextTick } from 'vue'
 import { ShapeFlags } from '@vue/shared'
+import merge from 'lodash/merge'
 
 import { DOMWrapper } from './dom-wrapper'
 import { WrapperAPI } from './types'
@@ -78,6 +79,13 @@ export class VueWrapper implements WrapperAPI {
     return Array.from(results).map((x) => new DOMWrapper(x))
   }
 
+  setData(data: Record<string, any>) {
+    // lodash.merge merges by *reference* so this will update
+    // any existing data with the newly passed data.
+    merge(this.componentVM.$data, data)
+    return nextTick()
+  }
+
   trigger(eventString: string) {
     const rootElementWrapper = new DOMWrapper(this.element)
     return rootElementWrapper.trigger(eventString)
diff --git a/tests/setData.spec.ts b/tests/setData.spec.ts
new file mode 100644
index 000000000..d88436cdf
--- /dev/null
+++ b/tests/setData.spec.ts
@@ -0,0 +1,67 @@
+import { mount } from '../src'
+
+describe('setData', () => {
+  it('causes nested nodes to re-render', async () => {
+    const Comp = {
+      template: `<div><div v-if="show" id="show">Show</div></div>`,
+      data() {
+        return { show: false }
+      }
+    }
+
+    const wrapper = mount(Comp)
+    expect(wrapper.find('#show').exists()).toBe(false)
+
+    await wrapper.setData({ show: true })
+
+    expect(wrapper.find('#show').exists()).toBe(true)
+  })
+
+  it('runs watch function when data is updated', async () => {
+    const Comp = {
+      template: `<div>{{ sideEffect }}</div>`,
+      data() {
+        return { msg: '', sideEffect: '' }
+      },
+      watch: {
+        msg() {
+          this.sideEffect = 'side effect'
+        }
+      }
+    }
+    const wrapper = mount(Comp)
+    expect(wrapper.html()).not.toContain('side effect')
+
+    await wrapper.setData({ msg: 'foo' })
+
+    expect(wrapper.html()).toContain('side effect')
+  })
+
+  it('updates a single property of a complex object', async () => {
+    const Comp = {
+      template: `<div>Qux: {{ foo.qux }}. Baz: {{ foo.bar.baz }}</div>`,
+      data() {
+        return {
+          foo: {
+            qux: 'will not change',
+            bar: {
+              baz: 'old val'
+            }
+          }
+        }
+      }
+    }
+    const wrapper = mount(Comp)
+    expect(wrapper.html()).toBe('<div>Qux: will not change. Baz: old val</div>')
+
+    await wrapper.setData({
+      foo: {
+        bar: {
+          baz: 'new val'
+        }
+      }
+    })
+
+    expect(wrapper.html()).toBe('<div>Qux: will not change. Baz: new val</div>')
+  })
+})
diff --git a/yarn.lock b/yarn.lock
index 784402de1..c4f4bd225 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1151,6 +1151,11 @@
   dependencies:
     jest-diff "^24.3.0"
 
+"@types/lodash@^4.14.149":
+  version "4.14.149"
+  resolved "https://registry.yarnpkg.com/@types/lodash/-/lodash-4.14.149.tgz#1342d63d948c6062838fbf961012f74d4e638440"
+  integrity sha512-ijGqzZt/b7BfzcK9vTrS6MFljQRPn5BFWOx8oE0GYxribu6uV+aA9zZuXI1zc/etK9E8nrgdoF2+LgUw7+9tJQ==
+
 "@types/node@*":
   version "13.7.4"
   resolved "https://registry.yarnpkg.com/@types/node/-/node-13.7.4.tgz#76c3cb3a12909510f52e5dc04a6298cdf9504ffd"