js 文件base64编码

function fileToBase64(file) {
  return new Promise((resolve, reject) => {
    const reader = new FileReader();
    reader.readAsDataURL(file);
    reader.onload = () => resolve(reader.result);
    reader.onerror = error => reject(error);
  });
}

// 使用示例
const input = document.createElement('input');
input.type = 'file';
input.onchange = async (event) => {
  const file = event.target.files[0];
  try {
    const base64 = await fileToBase64(file);
    console.log('Base64编码:', base64);
  } catch (error) {
    console.error('转换失败:', error);
  }
};
document.body.appendChild(input);

function urlSafeBase64Encode(str) {
  return str.replace(/\+/g, '-').replace(/\//g, '_').replace(/=+$/, '');
}

function urlSafeBase64Decode(str) {
  str = (str + '==='.slice((str.length + 3) % 4)).replace(/-/g, '+').replace(/_/g, '/');
  return atob(str);
}