I am checking for the existence of an object property with a variable holding the property name in question.
var myObj;
myObj.prop = "exists";
var myProp = "p"+"r"+"o"+"p";
if(myObj.myProp){
alert("yes, i have that property");
};
This is undefined because it's looking for myObj.myProp but I want it to check for myObj.prop
var myProp = 'prop';
if(myObj.hasOwnProperty(myProp)){
alert("yes, i have that property");
}
Or
var myProp = 'prop';
if(myProp in myObj){
alert("yes, i have that property");
}
Or
if('prop' in myObj){
alert("yes, i have that property");
}
Note that hasOwnProperty doesn't check for inherited properties, whereas in does. For example 'constructor' in myObj is true, but myObj.hasOwnProperty('constructor') is not.
Thank you for everyone's assistance and pushing to get rid of the eval statement. Variables needed to be in brackets, not dot notation. This works and is clean, proper code.
Each of these are variables: appChoice, underI, underObstr.
if(typeof tData.tonicdata[appChoice][underI][underObstr] !== "undefined"){
//enter code here
}