TypeError: Cannot read property '_id' of undefined
??? at D:\learning\web應用\NodeJS\code\imooc\app.js:88:26
代碼：//admin post movie
app.post('/admin/movie/new',function(req,res){
? var id = req.body.movie._id
? console.log('提交:'+id)

? var movieObj = req.body.movie
? var _movie

? if (id !== 'undefined') {
??? Movie.findById(id,function(err,movie){
????? if (err) {
??????? console.log(err)
????? }

????? _movie = _.extend(movie,movieObj)
????? _movie.save(function(err,movie){
??????? if (err) {
????????? console.log(err)
??????? }

??????? res.redirect('/movie/'+movie._id)
????? })
??? })
? }else{
??? _movie = new Movie({
????? doctor:movieObj.doctor,
????? title:movieObj.title,
????? country:movieObj.country,
????? language:movieObj.language,
????? year:movieObj.year,
????? poster:movieObj.poster,
????? summary:movieObj.summary,
????? flash:movieObj.flash
??? })

???? _movie.save(function(err,movie){
??????? if (err) {
????????? console.log(err)
??????? }

??????? res.redirect('/movie/'+movie._id)
??? })
? }
})

admin頁：extends ../layout

block content
??? .container
??????? .row
??????????? form.form-horizontal(method="post",action="/admin/movie/new")
???????????? input(type="hidden",name="movie[_id]",value="#{movie._id}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputTitle") 電影名字
??????????????? .col-sm-10
??????????????????? input#inputTitle.form-control(type="text",name="movie[title]",value="#{movie.title}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputDoctor") 導演
??????????????? .col-sm-10
??????????????????? input#inputDoctor.form-control(type="text",name="movie[doctor]",value="#{movie.doctor}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputCountry") 國家
??????????????? .col-sm-10
??????????????????? input#inputCountry.form-control(type="text",name="movie[country]",value="#{movie.country}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputLanguage") 語言
??????????????? .col-sm-10
??????????????????? input#inputLanguage.form-control(type="text",name="movie[language]",value="#{movie.language}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputPoster") 海報地址
??????????????? .col-sm-10
??????????????????? input#inputPoster.form-control(type="text",name="movie[poster]",value="#{movie.poster}")
????????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputFlash") 片源地址
??????????????? .col-sm-10
??????????????????? input#inputFlash.form-control(type="text",name="movie[flash]",value="#{movie.flash}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputYear") 上映年代
??????????????? .col-sm-10
??????????????????? input#inputYear.form-control(type="text",name="movie[year",value="#{movie.year}")
???????????? .form-group
??????????????? label.col-sm-2.control-label(for="inputSummary") 電影簡介
??????????????? .col-sm-10
??????????????????? input#inputSummary.form-control(type="text",name="movie[summary]",value="#{movie.summary}")
???????????? .form-group
??????????????? .col-sm-offset-2.col-sm-10
????????????????? button.btn.btn-default(type="submit") 錄入