从相对路径读取文件作为 ArrayBuffer

Question

I'm trying to read a local file into an ArrayBuffer using the FileReader API, like this

let reader = new FileReader();

reader.onload = function(e) {
    let arrayBuffer = new Uint8Array(reader.result);
    console.log(arrayBuffer);
}

reader.readAsArrayBuffer(new File([], 'data.txt'));

But I'm getting an empty arrayBuffer

How can I read this local file as an ArrayBuffer in my browser?

Thank you.

Answer 1

You cannot read a file by pathname through a browser. You need to have the user interact with the file system and choose a file before you can read the content.

 const readFile = e => { const file = e.target.files[0] let reader = new FileReader(); reader.onload = function(e) { let arrayBuffer = new Uint8Array(reader.result); console.log(arrayBuffer); } reader.readAsArrayBuffer(file); } document.querySelector("#fileItem").onchange=readFile

 <input id="fileItem" type="file">