类型错误：无法读取未定义的属性“indexOf”

Question

Node is giving this error while checking the occurrence of a substring:

TypeError: Cannot read property 'indexOf' of undefined'

 var withdraw = project.withdrawal; var uemail = user.eamil; var ans = withdraw.indexOf(uemail) > -1;

Answer 1

The variable withdraw is most likely undefined. Can you default it to an empty string with:

var withdraw = project.withdrawal || "";

That should avoid the error, but it might be better to check if there's another error causing withdrawal to be undefined.