Node 'crypto' SHA256 hashing model behavin

问题:

I have a function that takes a file and finds its SHA256 hash. Each time I resubmit a file, it produces a different hash for the same file.

On the first submission, it produces the correct hash. Each re-submission produces an incorrect hash. If I re-submit the same files in the same order, they all produce the same (incorrect) hash.

I think that the buffer might be building up. Or maybe something else? I'm trying to figure out how to clear the buffer array.

Any ideas?

import React, { Component } from "react";

const crypto = require("crypto");
const hash = crypto.createHash("sha256");

class SearchPage extends Component {
  constructor(props) {
    super(props);
    this.state = {
      hashOutput: "",
      fileName: "",
    };
  }

  onChange(e) {
    let files = e.target.files;
    this.setState({ fileName: files[0].name });
    let reader = new FileReader();
    reader.readAsArrayBuffer(files[0]);

    reader.onload = e => {
      hash.update(Buffer.from(e.target.result));
      const hashOutput = hash.digest("hex");
      this.setState({ hashOutput });
      console.log(hashOutput);
    };
  }

  render() {
    return (
        <div onSubmit={this.onFormSubmit}>
          <input type="file" name="file" onChange={e => this.onChange(e)} />
        </div>
    );
  }
}

export default SearchPage;