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expo-blob 为 React Native 提供了一个符合网页标准的 Blob 实现，具有更高的性能，并且在所有平台上都能稳定运行。与从 react-native 导出的实现相比，它更可靠，而 react-native 的 Blob 存在 slice() 方法及其他 Web API 功能上的限制。

安装

🌐 Installation

If you are installing this in an existing React Native app, make sure to install expo in your project.

用法

🌐 Usage

基本 Blob 创建

🌐 Basic blob creation

import { Blob } from 'expo-blob';

// Create an empty blob
const emptyBlob = new Blob();

// Create a blob from text
const textBlob = new Blob(['Hello, World!'], { type: 'text/plain' });

// Create a blob from binary data
const binaryBlob = new Blob([new Uint8Array([1, 2, 3, 4])], {
  type: 'application/octet-stream',
});

// Create a blob from mixed content
const mixedBlob = new Blob(
  [
    'Text content',
    new Uint8Array([65, 66, 67]), // ABC in ASCII
    'More text',
  ],
  { type: 'text/plain' }
);

Blob 属性

🌐 Blob properties

const blob = new Blob(['Hello, World!'], { type: 'text/plain' });

console.log(blob.size); // 13 (bytes)
console.log(blob.type); // "text/plain"

读取 Blob 内容

🌐 Reading blob content

const blob = new Blob(['Hello, World!'], { type: 'text/plain' });

// Read as text
const text = await blob.text();
console.log(text); // "Hello, World!"

// Read as bytes
const bytes = await blob.bytes();
console.log(bytes); // Uint8Array(13) [72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33]

// Read as ArrayBuffer
const arrayBuffer = await blob.arrayBuffer();
console.log(arrayBuffer); // ArrayBuffer(13)

切片 Blob

🌐 Slicing blobs

const blob = new Blob(['Hello, World!'], { type: 'text/plain' });

// Slice from position 0 to 5
const slice1 = blob.slice(0, 5);
console.log(await slice1.text()); // "Hello"

// Slice from position 7 to end
const slice2 = blob.slice(7);
console.log(await slice2.text()); // "World!"

// Slice with custom type
const slice3 = blob.slice(0, 5, 'text/html');
console.log(slice3.type); // "text/html"

流式

🌐 Streaming

const blob = new Blob(['Large content...'], { type: 'text/plain' });

// Create a readable stream
const stream = blob.stream();
const reader = stream.getReader();

// Read chunks
while (true) {
  const { done, value } = await reader.read();
  if (done) break;
  console.log('Chunk:', value);
}

应用接口

🌐 API

Classes

Types