samples/this_for_eval.js

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// how to pass arbitrary "this" object for eval'ed script?

var obj = { foo: 44 };

// the following won't work. eval.apply is indirect eval call
// and so 'this' will be global object always! So, this
// line will print 'undefined'
eval.apply(obj, [ " print(this.foo)" ]);

obj.myEval = eval;

// still won't work - still indirect 'eval' call!
// still undefined is printed!
obj.myEval("print(this.foo)");

function func(code) {
    eval(code);
}

// eval called inside func and so get's func's "this" as it's "this"!
// So, 44 is printed

func.apply(obj, [ "print(this.foo)" ]);