Object is not extensible error when creating new attribute for array of objects

[梵总]

const tableData = this.state.uploadedFiles.map((file) => {
      const url = file.url;
      const filename = file.filename;
      console.log(url);
      file.action = this.deleteButton(file);
      file.downloadUrl = (
        <a href="#" onClick={(e) => this.handleDownload(e, url, filename)}>
          {url}
        </a>
      );
      return file;
    });

Have to create a new object

const tableData = this.state.uploadedFiles.map((file) => {
      const newFile = Object.assign({}, file);
      const url = file.url;
      const filename = file.filename;
      console.log(url);
      newFile.action = this.deleteButton(file);
      newFile.downloadUrl = (
        <a href="#" onClick={(e) => this.handleDownload(e, url, filename)}>
          {url}
        </a>
      );
      return newFile;
    });

https://stackoverflow.com/questions/45798885/object-is-not-extensible-error-when-creating-new-attribute-for-array-of-objects