无法读取未定义node.js的属性“长度”
我有一些JSON传递到Node.js，我试图通过它parsing并显示在页面上。 然而，在searchStack Overflow并尝试了各种解决scheme（目前正在阅读本文 ）之后，我收到了这个错误：
TypeError: D:\Programming\node\yale\views\index.jade:10 8| //- p= post.comments[1].data 9| each comment in post.comments > 10| each text in comment.data 11| p= text.from.name 12| 13| Cannot read property 'length' of undefined at $$l (eval at <anonymous> (D:\Programming\node\yale\node_modules\jade\lib\jade.js:172:8), <anonymous>:122:31) at $$l (eval at <anonymous> (D:\Programming\node\yale\node_modules\jade\lib\jade.js:172:8), <anonymous>:153:4) at eval (eval at <anonymous> (D:\Programming\node\yale\node_modules\jade\lib\jade.js:172:8), <anonymous>:160:4) at eval (eval at <anonymous> (D:\Programming\node\yale\node_modules\jade\lib\jade.js:172:8), <anonymous>:301:4) at eval (eval at <anonymous> (D:\Programming\node\yale\node_modules\jade\lib\jade.js:172:8), <anonymous>:311:21) at res (D:\Programming\node\yale\node_modules\jade\lib\jade.js:173:38) at Object.exports.render (D:\Programming\node\yale\node_modules\jade\lib\jade.js:269:10) at Object.exports.renderFile (D:\Programming\node\yale\node_modules\jade\lib\jade.js:305:18) at View.exports.renderFile [as engine] (D:\Programming\node\yale\node_modules\jade\lib\jade.js:290:21) at View.render (D:\Programming\node\yale\node_modules\express\lib\view.js:76:8) 这是我的JSON：
[ { "id": "362285220481827_740014816042197", "from": { "id": "1677018201", "name": "ABC" }, "message": "Yo!", "comments": { "data": [ { "id": "740018622708483", "from": { "id": "100003969443486", "name": "XTZ" }, "message": "Hey!", "can_remove": false, "created_time": "2014-06-14T17:18:48+0000", "like_count": 0, "user_likes": false } ], "paging": { "cursors": { "after": "NzQ0MTMxNTc1NjMwNTIx", "before": "NzQwMDE4NjIyNzA4NDgz" } } } } ]
Index.jade
扩展布局
block content each post in datas div(id='post') p= post.from.name p= post.message //- p= post.comments[1].data each comment in post.comments each text in comment.data p= text.from.name
Index.js
var express = require('express'); var router = express.Router(); var fs = require('fs'); var path = require('path'); var file = '../public/sample.json'; var filePath = path.join(__dirname, '../public/sample.json'); /* GET home page. */ router.get('/', function(req, res) { fs.readFile(filePath, 'utf8', function(err, data) { if(err) { console.log(err); } else { data = JSON.parse(data); res.render('index', { datas: data }); console.log(data); } }); }); module.exports = router;
我的问题是，如何检索Comments对象内的数据？ 谢谢你的帮助！
我想你想要迭代post数据，而不是对象本身。
each comment in post.comments.data p= comment.from.name
comments不是JSON结构中的数组，它是一个对象。 尝试使它成为一个数组。