Uncaught TypeError: Cannot read property 'label' of undefined

[SmartLyu]

gitbook build is OK, but web serve is error

web error is :
Uncaught TypeError: Cannot read property 'label' of undefined
at buttons.js:44
at Function.map (gitbook.js:1)
at Object. (buttons.js:40)
at Object.dispatch (gitbook.js:2)
at Object.m.handle (gitbook.js:2)
at Object.trigger (gitbook.js:3)
at Object. (gitbook.js:3)
at Function.each (gitbook.js:1)
at de.fn.init.each (gitbook.js:1)
at de.fn.init.trigger (gitbook.js:3)

gitbook version is:
CLI version: 2.3.2
GitBook version: 3.2.3

[wood-j]

I have some simular issue, may be because the nodejs updated and this project totally abandon.