javascript - Jade when passing object/array from router get error -

javascript - Jade when passing object/array from router get error -

i'm exploring jade view engine in node , spent 3 hours not beingness able pass object (the response database) jade view without getting error.

from router all array objects:

var router = express.router(); router.get('/all', function(req, res){ db.findall().then(function(all){ res.render("index", { creators: }); }); });

jade view:

doctype html html head title jade template body .comment_list each el in creators p= el.creator

as see it's pretty simple. i've seen more 20 examples of using jade , same , error:

> typeerror: index.jade:7 5| body 6| .comment_list > 7| each el in creators 8| p= el.creator cannot read property 'length' of undefined

until tried check if(typeof(creators) != "undefined") before each el in creators , guess what... magic happened. error disappeared.

i'm writing post reference people struggling same issuse , i'd inquire reason error , why in documentation of jade mentioned 1 should create such check undefined before iterating through collection?

it mutual pattern in jade check variable's existence before trying operate on it.

from jade documentation on iterations:

the object or array iterate on plain javascript can variable or result of function phone call or else.

- var values = []; ul each val in values.length ? values : ['there no values'] li= val

under hood, jade using standard javascript when phone call each.

so trying phone call each on doesn't exist trying do:

for(var i=0; < undefined.length; i++) { ... }

which errors because length isn't real property of undefined.

totally understand frustration, dealing undefined info pains lot of people in javascript.

javascript node.js express jade