node.js - 错误：命令失败：无效参数 - -resize

Question

const express = require('express');

const multer = require('multer');

var fs = require('fs')
  , gm = require('gm').subClass({imageMagick: true});
  
const router = express.Router();


const storage = multer.diskStorage({
    destination: (req, file, cb) => {
        cb(null, './public/images')
    }, 
    filename: (req, file, cb) => {
        cb(null, file.originalname + '-' + Date.now() + '.png')
    }
})

var upload = multer({ storage: storage }).single('image');

router.get('/', (req, res, next) => {
    res.render('index', {
        title: 'Express'
    })
});

router.post('/', upload, (req, res, next) => {
    gm(req.file.path)
    .resize(240, 240)
    .gravity('Center')
    .extent(240, 240)
    .noProfile()
    .write('./public/images/update/' + req.file.originalname + '-' + Date.now(), function(err){
        console.log('err', err);
    })
})


module.exports = router;