Jade Cannot read property 'length' of undefined

问题

Why menuItems is undefined in the following code?

- var menuItems = ["Main","Contacts","About"]
mixin showItems(items)
    ul
        each item in items
            li: a(href="#") #{item}
extend layout
block content
    +showItems(menuItems)

I get the following error:

Cannot read property 'length' of undefined

回答1:

- var menuItems = ["Main","Contacts","About"]
mixin showItems(items)
    ul
        each item in items
            li: a(href="#") #{item}
extends layout
block content
    +showItems(menuItems)

There is a Typo 'extends layout'

来源：https://stackoverflow.com/questions/34283251/jade-cannot-read-property-length-of-undefined