feat: add readFile

src/index.ts

@@ -8,5 +8,6 @@ export * from './utils/indent'
 export * from './utils/isChineseIDCardNumber'
 export * from './utils/isPossibleChineseMobilePhoneNumber'
 export * from './utils/isUrl'
+export * from './utils/readFile'
 export * from './utils/wait'
 // @endindex

src/utils/readFile.test.ts

@@ -0,0 +1,49 @@
+import { base64Encode } from './base64'
+import { readFile } from './readFile'
+import { TextDecoder, TextEncoder } from 'util'
+
+describe(readFile.name, () => {
+  test('text should work', async () => {
+    const expectedText = 'vtils'
+    const actualText = await readFile(new File([expectedText], 'x')).text()
+    expect(actualText).toBe(expectedText)
+  })
+
+  test('json should work', async () => {
+    const expectedJson = { a: 1 }
+    const actualJson = await readFile(
+      new File([JSON.stringify(expectedJson)], 'x'),
+    ).json<typeof expectedJson>()
+    expect(actualJson).toEqual(expectedJson)
+  })
+
+  test('dataUrl should work', async () => {
+    const expectedType = 'text/plain'
+    const expectedData = 'hello'
+    const expectedDataUrl = `data:${expectedType};base64,${base64Encode(
+      expectedData,
+    )}`
+    const actualDataUrl = await readFile(
+      new File([expectedData], 'x', { type: expectedType }),
+    ).dataUrl()
+    expect(actualDataUrl).toBe(expectedDataUrl)
+  })
+
+  test('base64 should work', async () => {
+    const expectedData = 'hello'
+    const expectedBase64 = base64Encode(expectedData)
+    const actualBase64 = await readFile(new File([expectedData], 'x')).base64()
+    expect(actualBase64).toBe(expectedBase64)
+  })
+
+  test('arrayBuffer should work', async () => {
+    const expectedData = 'hello'
+    const expectedArrayBuffer = new TextEncoder().encode(expectedData)
+    const actualArrayBuffer = await readFile(
+      new File([expectedArrayBuffer], 'x'),
+    ).arrayBuffer()
+    expect(new TextDecoder('utf-8').decode(actualArrayBuffer)).toBe(
+      expectedData,
+    )
+  })
+})

src/utils/readFile.ts

@@ -0,0 +1,91 @@
+export interface ReadFileResult {
+  /**
+   * Returns the text contents.
+   */
+  text(): Promise<string>
+
+  /**
+   * Returns the JSON contents.
+   */
+  json<T>(): Promise<T>
+
+  /**
+   * Returns the dataURL contents.
+   */
+  dataUrl(): Promise<string>
+
+  /**
+   * Returns the base64 contents.
+   */
+  base64(): Promise<string>
+
+  /**
+   * Returns the ArrayBuffer contents.
+   */
+  arrayBuffer(): Promise<ArrayBuffer>
+}
+
+/**
+ * Reads the contents of the given file.
+ *
+ * @param file The given file.
+ * @returns Returns the contents getters.
+ */
+export function readFile(file: File): ReadFileResult {
+  const text: ReadFileResult['text'] = () => {
+    return new Promise((resolve, reject) => {
+      const fileReader = new FileReader()
+      fileReader.onload = () => {
+        resolve(fileReader.result as string)
+      }
+      fileReader.onerror = () => {
+        reject(fileReader.error)
+      }
+      fileReader.readAsText(file)
+    })
+  }
+
+  const json: ReadFileResult['json'] = () => {
+    return text().then(data => {
+      try {
+        return JSON.parse(data)
+      } catch (err) {
+        return Promise.reject(err)
+      }
+    })
+  }
+
+  const dataUrl: ReadFileResult['dataUrl'] = () => {
+    return new Promise((resolve, reject) => {
+      const fileReader = new FileReader()
+      fileReader.onload = () => {
+        resolve(fileReader.result as string)
+      }
+      fileReader.onerror = () => {
+        reject(fileReader.error)
+      }
+      fileReader.readAsDataURL(file)
+    })
+  }
+
+  const base64: ReadFileResult['base64'] = () => {
+    return dataUrl().then(url => {
+      return url.split(';base64,')[1]
+    })
+  }
+
+  const arrayBuffer: ReadFileResult['arrayBuffer'] = () => {
+    return new Promise((resolve, reject) => {
+      const fileReader = new FileReader()
+      fileReader.onload = () => {
+        resolve(fileReader.result as ArrayBuffer)
+      }
+      fileReader.onerror = () => {
+        reject(fileReader.error)
+      }
+      fileReader.readAsArrayBuffer(file)
+    })
+  }
+
+  return { text, json, dataUrl, base64, arrayBuffer }
+}