Move toolbar functionality from redux to codemirror dispatch (#2083)

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

src/utils/read-file.test.ts

@@ -0,0 +1,18 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { FileContentFormat, readFile } from './read-file'
+
+describe('read file', () => {
+  it('reads files as text', async () => {
+    const a = await readFile(new Blob(['Kinderriegel'], { type: 'text/plain' }), FileContentFormat.TEXT)
+    expect(a).toBe('Kinderriegel')
+  })
+  it('reads files as data url', async () => {
+    const a = await readFile(new Blob(['Kinderriegel'], { type: 'text/plain' }), FileContentFormat.DATA_URL)
+    expect(a).toBe('data:text/plain;base64,S2luZGVycmllZ2Vs')
+  })
+})

src/utils/read-file.ts

@@ -0,0 +1,40 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+export enum FileContentFormat {
+  TEXT,
+  DATA_URL
+}
+
+/**
+ * Reads the given {@link File}.
+ *
+ * @param file The file to read
+ * @param fileReaderMode Defines as what the file content should be formatted.
+ * @throws Error if an invalid read mode was given or if the file couldn't be read.
+ * @return the file content
+ */
+export const readFile = async (file: Blob, fileReaderMode: FileContentFormat): Promise<string> => {
+  return new Promise<string>((resolve, reject) => {
+    const fileReader = new FileReader()
+    fileReader.addEventListener('load', () => {
+      resolve(fileReader.result as string)
+    })
+    fileReader.addEventListener('error', (error) => {
+      reject(error)
+    })
+    switch (fileReaderMode) {
+      case FileContentFormat.DATA_URL:
+        fileReader.readAsDataURL(file)
+        break
+      case FileContentFormat.TEXT:
+        fileReader.readAsText(file)
+        break
+      default:
+        throw new Error('Unknown file reader mode')
+    }
+  })
+}