I have a statement in my code:
if(!(typeof options.duration[i] === 'undefined'))
I have written it correctly, seems that there is no mistake but the console is throwing error that:
TypeError: options.duration is undefined
It should not show this error.It does not make any sense.
The variable options.duration
is undefined, so accessing item i
from it will result in this error. Perhaps try:
if(typeof options.duration !== 'undefined')
Or if you need to check both options.duration
and options.duration[i]
, try
if(typeof options.duration !== 'undefined' &&
typeof options.duration[i] !== 'undefined')
为了使测试成功,还必须定义数组options.duration
本身。
You get that error because the duration
property doesn't exist.
Check if the property exists before you try to check items in it:
if('duration' in options && typeof options.duration[i] !== 'undefined')
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.