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HomeWeb Front-endJS TutorialHow to convert file object to json object in js

File objects cannot be converted directly to JSON objects. Preprocessing steps include: reading file content, encoding content, and creating JSON objects. For example, use the FileReader API to read file content, encode it to Base64, and create a JSON object with the encoded content as a value.

How to convert file object to json object in js

How to convert a File object in JavaScript to a JSON object

Direct answer:

File objects cannot be converted directly to JSON objects.

Detailed answer:

File objects contain binary data, while JSON objects can only contain text data such as strings and numbers. Therefore, File objects need to be preprocessed before they can be converted into JSON objects.

Preprocessing steps:

  1. #Read file content: Use FileReader API to read the File object Content.
  2. Encoding content: Encode the read content into text format, such as Base64.
  3. Create JSON object: Use the encoded content as the value to create a new JSON object.

Sample code:

// 创建 FileReader 实例
const reader = new FileReader();

// 监听文件读取事件
reader.onload = function() {
  // 读取到的内容
  const content = reader.result;

  // 将内容编码为 Base64
  const encodedContent = btoa(content);

  // 创建 JSON 对象
  const jsonObject = {
    content: encodedContent,
  };

  // 输出 JSON 对象
  console.log(jsonObject);
};

// 开始读取文件
reader.readAsArrayBuffer(file);

Note:

  • Content encoded as Base64 may increase The size of the file.
  • For large files, they can be read in chunks to improve efficiency.
  • Use the JSON.stringify() method to convert a JSON object into a string.

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