testsrc.doctests.arguments.doctest Maven / Gradle / Ivy

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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

js> var args = (function() { return arguments })()
js> Object.getPrototypeOf(args) === Object.prototype
true
js> args.constructor === Object.prototype.constructor
true
js> Object.getOwnPropertyDescriptor(args, 'constructor').toSource();
({value:function Object() { [native code for Object.Object, arity=1] }
, writable:true, enumerable:false, configurable:true})

js> args.toString()
[object Arguments]

js> var toStr = Object.prototype.toString;
js> var _ = Object.prototype.toString = function() { 
  >   return this === args ? 
  >     "executes Object.prototype.toString.call(arguments)" : 
  >     "'this' should be 'arguments'"
  > }
js> args.toString()
executes Object.prototype.toString.call(arguments)
js> Object.prototype.toString = toStr; undefined

js> var toLocStr = Object.prototype.toLocaleString;
js> var _ = Object.prototype.toLocaleString = function() { 
  >   return this === args ? 
  >     "executes Object.prototype.toLocaleString.call(arguments)" : 
  >     "'this' should be 'arguments'"
  > }
js> args.toLocaleString()
executes Object.prototype.toLocaleString.call(arguments)
js> Object.prototype.toLocaleString = toLocStr; undefined;

js> (function() { return arguments[2] })('a','b','c')
c
js> (function(x,y,z) { return arguments[2] })('a','b','c')
c

js> (function(x) { 
  >   arguments[0] = "modified"; 
  >   return x; 
  > })("original")
modified

js> (function(x) { 
  >   x = "modified"; 
  >   return arguments[0]; 
  > })("original")
modified

js> (function(x) { 
  >   delete arguments[0]; 
  >   arguments[0] = "modified"; 
  >   return x; 
  > })("original")
original

js> (function(x) { 
  >   delete x;
  >   var x = "modified";
  >   return arguments[0]
  > })("original")
modified

js> (function(x) { 
  >   Object.defineProperty(arguments, 0, {get:function(){return "modified"}});
  >   return arguments[0]; 
  > })("original")
modified

js> (function(x) { 
  >   Object.defineProperty(arguments, 0, {get:function(){return "modified"}});
  >   return x; 
  > })("original")
original

js> (function(x) { 
  >   Object.defineProperty(arguments, 0, {value:"modified"});
  >   return arguments[0]; 
  > })("original")
modified

js> (function(x) { 
  >   Object.defineProperty(arguments, 0, {value:"modified"});
  >   return x; 
  > })("original")
modified

js> (function() { for (var i in arguments) print(i); })('a','b','c')
0
1
2

js> (function() { 
  >   arguments.a = 1; 
  >   Object.defineProperty(arguments, 'b', {value:2, enumerable:true});
  >   Object.defineProperty(arguments, 'c', {value:3, enumerable:false});
  >   Object.defineProperty(arguments, 0, {enumerable:false});
  >   for (var p in arguments) print(p);
  > })('hi')
a
b

js> (function() { return Object.getOwnPropertyDescriptor(arguments, 0) === undefined })()
true

js> (function() { return Object.getOwnPropertyDescriptor(arguments, 0).toSource(); })("a")
({value:"a", writable:true, enumerable:true, configurable:true})

js> (function(x) { 
  >   Object.defineProperty(arguments, 0, {enumerable:false});
  >   return Object.getOwnPropertyDescriptor(arguments, 0).enumerable;
  > })("original")
false

js> (function() { 
  >   Object.defineProperty(arguments, 0, {value:2, writable:false});
  >   arguments[0] = 3;
  >   return arguments[0];
  > })(1); 
2