How can I stop "property does not exist on type JQuery" syntax errors when using Typescript?

You could cast it to <any> or extend the jquery typing to add your own method.

 (<any>$("div.printArea")).printArea();

//Or add your own custom methods (Assuming this is added by yourself as a part of custom plugin)

interface JQuery {
    printArea():void;
}

I think this is the most readable solution:

($("div.printArea") as any).printArea();

You can cast it to

(<any>$('.selector') ).function();

Ex: date picker initialize using jquery

(<any>$('.datepicker') ).datepicker();