Refresh markdown preview on updating configuration

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- Refresh Markdown preview on updating configuration (for VSCode >= 1.34) ([#20](https://github.com/marp-team/marp-vscode/pull/20))
 - Use Marp Core options when rendering by Marp ([#21](https://github.com/marp-team/marp-vscode/pull/21))
 
 ## v0.1.0 - 2019-03-22

src/__mocks__/vscode.ts

@@ -1,3 +1,4 @@
 export const workspace = {
   getConfiguration: jest.fn(() => new Map()),
+  onDidChangeConfiguration: jest.fn(),
 }

src/extension.test.ts

@@ -32,8 +32,18 @@ beforeEach(() => mockWorkspaceConfig())
 afterEach(() => jest.restoreAllMocks())
 
 describe('#activate', () => {
-  it('contains #extendMarkdownIt', () =>
-    expect(activate()).toEqual(expect.objectContaining({ extendMarkdownIt })))
+  const extContext: any = { subscriptions: { push: jest.fn() } }
+
+  it('contains #extendMarkdownIt', () => {
+    expect(activate(extContext)).toEqual(
+      expect.objectContaining({ extendMarkdownIt })
+    )
+  })
+
+  it('starts tracking to change of configurations', () => {
+    const onDidChgConf = workspace.onDidChangeConfiguration as jest.Mock
+    expect(onDidChgConf).toBeCalledWith(expect.any(Function))
+  })
 })
 
 describe('#extendMarkdownIt', () => {

src/extension.ts

@@ -1,10 +1,11 @@
 import { Marp } from '@marp-team/marp-core'
-import { workspace } from 'vscode'
+import { ExtensionContext, commands, workspace } from 'vscode'
 
 const frontMatterRegex = /^-{3,}\s*([^]*?)^\s*-{3}/m
 const marpDirectiveRegex = /^marp\s*:\s*true\s*$/m
 const marpConfiguration = () => workspace.getConfiguration('markdown.marp')
 const marpVscode = Symbol('marp-vscode')
+const shouldRefreshConfs = ['markdown.marp.enableHtml', 'window.zoomLevel']
 
 const detectMarpFromFrontMatter = (markdown: string): boolean => {
   const m = markdown.match(frontMatterRegex)
@@ -51,4 +52,14 @@ export function extendMarkdownIt(md: any) {
   return md
 }
 
-export const activate = () => ({ extendMarkdownIt })
+export const activate = ({ subscriptions }: ExtensionContext) => {
+  subscriptions.push(
+    workspace.onDidChangeConfiguration(e => {
+      if (shouldRefreshConfs.some(c => e.affectsConfiguration(c))) {
+        commands.executeCommand('markdown.preview.refresh')
+      }
+    })
+  )
+
+  return { extendMarkdownIt }
+}