Use XLSX to convert the uploaded file stream into an array

	方法：
		getChangeFile(file){
    
    
			this.fileToArr(file).then(item=>{
    
    
				if(item&&item.length>0){
    
    
					if(item[0]&&item[0].sheet&&item[0].sheet.length){
    
    
						const fileInfo = item[0].sheet;
						this.Arr = fileInfo;// 这个就是需要的结果
						}
				}
			}).catch()
			},
		fileToArr(file){
    
    
			return new Promise(resolve =>{
    
    
				const reader = new FileReader();
				reader.onload = function(e){
    
    
					const data = e.target.reault;
					this.wb = XLSX.read(data, {
    
    type: 'binary'})
					const result = [];
					this.wv.SheetNames.forEach(sheetName =>{
    
    
						result.push({
    
    sheetName,sheet:XLSX.utils.sheet_to_json(this.wb.Sheets[sheetName])});
						});
						resolve(result)
					}
				reader.readAsBinaryString(file.raw);
				});
			}