eval - make javascript literal inheriting from different prototype -
i have code goes against practice. however, not want comments on - purely academic.
<html> <head> <script> function run() { var fakecontext = { array : fr.contentwindow.array || fr.array; //another context/window array } fakecontext.array.prototype.remove = function(el) {/*some code*/}; (fakecontext) { var somecode = "var x = ['1', '2']; x.remove('2')"; eval(somecode); } } </script> </head> <body> <iframe src="about:blank" name="fr"></iframe> </body> </html> this array created when evaluating somecode inherits top level array in code runs instead of inheriting fakecontext.array. meaning array x not have prototype function .remove()
how can (if there way) literals in somecode-string inherit fakecontexts array.prototype?
the problem array literal [] not evaluate in same way new array(). first create native array object, while second checks scope array variable , executes constructor.
var fakewin = fr.contentwindow || fr; var fakecontext = {array: fakewin.array}; (fakecontext) { array.prototype.remove = function(el) {/*some code*/}; eval("var x = new array('1', '2'); x.remove('2')"); } to create arrays prototype different context, need eval literals in fake window environment:
var fakewin = fr.contentwindow || fr; (fakewin) { array.prototype.remove = function(el) {/*some code*/}; eval("var x = new array('1', '2'); x.remove('2')"); } // or: fakewin.array.prototype.remove = function(el) {/*some code*/}; fakewin.eval("var x = new array('1', '2'); x.remove('2')");
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