如何将文本保存到文件并再次读取，但在javascript中保存为二进制文件

How to save a text to file and read it again but save as binary in javascript

本文关键字：javascript 但在 保存 二进制文件 读取 文本 存到文件      更新时间：2023-09-26

我正在从一个SO问题中使用filesver .js从字符串中构建一个文件保存程序

let byteChars = atob("my string");
let byteNumbers = new Array(byteChars.length);
for (var i = 0; i < byteChars.length; i++) {
  byteNumbers[i] = byteChars.charCodeAt(i);
}
let byteArray = new Uint8Array(byteNumbers);
var data:Blob = new Blob([byteArray], {type: "application/octet-stream"});
var filename:string = filename + '.myext';
saveAs(data, filename, true);

然后我必须读回"my string"使用Javascript的FileReader:

let fr = new FileReader();
fr.onload = (e:FileReaderEvent) => {
    let result:any = e.target.result;
    //I don't know what I have to do with this type of data to get "my string" back
    };
fr.readAsBinaryString(file);

编辑，更新

写文件

let byteChars = atob("my string");
let byteNumbers = new Array(byteChars.length);
for (var i = 0; i < byteChars.length; i++) {
  byteNumbers[i] = byteChars.charCodeAt(i);
}
let byteArray = new Uint8Array(byteNumbers);
var data = new Blob([byteArray], {type: "application/octet-stream"});
saveAs(data, "myfile.abc");

读文件

<input type="file">
<script>
 var reader = new FileReader();
 reader.addEventListener("load", function(e) {
   document.body.innerHTML += "<br>" + btoa(e.target.result);
 });
  document.querySelector("input[type=file]")
  .addEventListener("change", function(e) {
     reader.readAsBinaryString(e.target.files[0])
  })
</script>

plnkr http://plnkr.co/edit/0KVhXnd0JpysplDLcAlC?p=preview

您可以使用TextEncoder(), TextDecoder()或FileReader(), .readAsBinaryString() 

var str = "my string";
var encoder = new TextEncoder();
var encodedBytes = encoder.encode(str);
// do file save stuff
var decoder = new TextDecoder();
var decodedBytes = decoder.decode(encodedBytes);
console.log(encodedBytes, decodedBytes);
// alternatively, using `FileReader()`
var reader = new FileReader();
reader.onload = function() {
  console.log("FileReader result:", reader.result)
}
reader.readAsBinaryString(new Blob([encodedBytes]))

相关文章：