JS工具函数 #

const Base64ConvertToImage = (saveName, b64Info, contType) => { /** base64文件流并保存到本地png/jpg*/
  const b64toBlob = (b64Data, contentType = "image/png", sliceSize = 512) => {
  //-- parse base64 string
  const byteCharacters = window.atob(b64Data);
  const byteArrays = [];
  for (let offset = 0; offset < byteCharacters.length; offset += sliceSize) {
    const slice = byteCharacters.slice(offset, offset + sliceSize);
    const byteNumbers = new Array(slice.length);
    for (let i = 0; i < slice.length; i++) {
      byteNumbers[i] = slice.charCodeAt(i);
    }
    //-- https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array
    const byteArray = new Uint8Array(byteNumbers);
    byteArrays.push(byteArray);
  }
    //-- https://developer.mozilla.org/zh-CN/docs/Web/API/Blob
    const blob = new Blob(byteArrays, { type: contentType });
    return blob;
  }
  const blob = b64toBlob(b64Info, contType);
  //-- https://developer.mozilla.org/zh-CN/docs/Web/API/URL/createObjectURL
  //-- URL.createObjectURL() 静态方法会创建一个 DOMString
  const blobUrl = URL.createObjectURL(blob);

  const aEle = document.createElement("a");
  const evt = document.createEvent("HTMLEvents");
  //-- 初始化，事件类型，是否冒泡，是否阻止浏览器的默认行为
  evt.initEvent("click", true, true);
  aEle.download = saveName;
  aEle.href = blobUrl;
  aEle.click();
}
export default Base64ConvertToImage;

let timeStr = '20190526153600'
timeStr = timeStr.replace(/^(\d{4})(\d{2})(\d{2})(\d{2})(\d{2})(\d{2})$/, '$1-$2-$3 $4:$5:%6')
console.log(timeStr) //- - 2019-05-25 15:36:00

let dtDate = '2019年05月26日 15:40:23'
dtDate = dtDate.replace(/(\d{4}).(\d{1,2}).(\d{1,2}).+/mg, '$1-$2-$3')
console.log(dtDate) //- - 2019-05-26

let dtData = '2019年05月26日 15:40:23'
dtDate = dtDate.replace(/[^[0-9]]/mg,'').match(/.\d{8}/)
console.log(dtDate) //- - 20190526