js: 从base64编码中解析图片信息

/**
 * 从base64编码中解析图片信息
 * @param {String} base64
 * @returns {Object}
 */
function parseBase64(base64) {
  let re = new RegExp('data:(?<type>.*?);base64,(?<data>.*)')
  let res = re.exec(base64)
  if (res) {
    return {
        type: res.groups.type,
        ext: res.groups.type.split('/').slice(-1)[0],
        data: res.groups.data,
    }
  }
}

let base64 = 'data:image/gif;base64,R0lGODlhAQABAPcAAAuvCwu1Cwy6DAy/DA'
let info = parseBase64(base64)
console.log(info);

{
    type: 'image/gif',
    ext: 'gif',
    data: 'R0lGODlhAQABAPcAAAuvCwu1Cwy6DAy/DA'
}