JavaScript错误“未定义不是对象”

Question

I am attempting to debug javascript that runs inside Adobe indesign. The first executable line returns an "undefined is not an object"

if ( app.documents.length==0 ) { exit(); }

Could Adobe have moved the nested object "documents" to a higher level?

Answer 1

Your code can be safe but to be effective make sure script is properly targeted. Ie if your debug is processing from ESTK - choose a target application from left-up corner dropdownlist or place this line in code's very top:

#target indesign 

Answer 2

Cashmirek is probably right. If you are running your script from inside ExtendScript ToolKit, you need to either type in the #target instruction or pick InDesign in the application list.

Answer 3

To be safe I would suggest, you use something like this:

if (app === undefined || app.documents === undefined || app.documents.length === 0) { 
    exit();
}

The exit() will be performed if app or app.documents or app.documents.length is undefined or app.documents.length is 0 . It eliminates the exception problem, because Javascript will stop evaluating the conditions, after one found 'true'.

Be sure to use === instead of == to ensure type comparison.

Hope that helps