回答

js代码

     var editor = grapesjs.init( {
            showOffsets: 1,
            noticeOnUnload: 0,
            container: '#gjs',
            height: '100%',
            storageManager: false,
            plugins: [
             ],
            assetManager: {
                upload: 'upload.php',
                assets:assetdata,
                uploadFile: (e) => {
                    const formData = new FormData();
                    var files = e.dataTransfer ? e.dataTransfer.files: e.target.files;
                    for (let i = 0; i < files.length; i++) {
                        formData.append('files[]', files[i]);
                    }

                    fetch('/upload.php', {
                        method: 'POST',

                        body: formData
                    })
                    .then(response => response.json())
                    .then(data => {
                        assetdata.push(data);
                        console.log('上传成功！', data);
                        var myJSON = [];

                        $.each(data, function(key, value) {
                            myJSON[key] = value;

                        });
         var images = myJSON;
                        // 更新资源管理器和预览区域中的文件列表
                        editor.AssetManager.add(images);
                    })
                    .catch(error => console.error('上传失败！', error));
                },
                uploadName: 'files',
                // 上传文件的名称
                headers: {
                    // 请求头
                    'Authorization': 'Bearer token'
                }
            },
            fromElement: false,

        });

<?php
$uploadDir = 'uploadfolder/'; // 上传文件的目录

if (!empty($_FILES['files']['name'][0])) {
  $ret=[];
  // 遍历上传的所有文件
  foreach ($_FILES['files']['name'] as $key => $value) {

    $fileName = basename($_FILES['files']['name'][$key]);
    $targetFile = $uploadDir . $fileName;
    $fileType = pathinfo($targetFile, PATHINFO_EXTENSION);

    // 判断文件类型是否允许上传
    if (in_array($fileType, array('jpg', 'jpeg', 'png', 'gif'))) {
      // 将文件从临时目录移动到上传目录
      if (move_uploaded_file($_FILES['files']['tmp_name'][$key], $targetFile)) {
        // 生成返回数据
        $ret[] = array(
          'src' => $targetFile,
          'name' => $fileName,
          'type' => $_FILES['files']['type'][$key],
          'size' => $_FILES['files']['size'][$key]
        );

        //将返回数据转换为JSON格式，并输出到客户端

      }
    }
  }
  echo json_encode($ret);
}