calling eval() in particular context

Question

I have following javaScript \"class\":

A = (function() {
   a = function() { eval(...) };
   A.prototype.b = function(arg1, arg2) { /* do something... */};
}         


        

Answer 1

definitely not the right answer, and please do not use with statement, unless you know what you're doing, but for the curious, you can do this

Example

    var a = {b: "foo"};
    with(a) {
        // prints "foo"
        console.log(eval("b"));  
        
        // however, "this.b" prints undefined
        console.log(eval("this.b"));
    
        // because "this" is still the window for eval
        // console.log(eval("this")); // prints window

// if you want to fix, you need to wrap with a function, as the main answer pointed out
        (function(){
	         console.log(eval("this.b")); // prints foo
        }).call(a);     
    }
    
    // so if you want to support both    
    with (a) {
    	(function (){
        console.log("--fix--");
      	console.log(eval("b")); // foo
        console.log(eval("this.b")); // foo
      }).call(a);
    }

with is the failed attempt to create block scopes within functions, kind of what the ES6's let is designed to do. (but not exactly, open and read the resource links)