diff --git a/lib/coffee-script/helpers.js b/lib/coffee-script/helpers.js
index b0a997b8d6..18a2fad20b 100644
--- a/lib/coffee-script/helpers.js
+++ b/lib/coffee-script/helpers.js
@@ -1,6 +1,6 @@
 // Generated by CoffeeScript 1.3.3
 (function() {
-  var extend, flatten;
+  var extend, flatten, _ref;
 
   exports.starts = function(string, literal, start) {
     return literal === string.substr(start, literal.length);
@@ -74,4 +74,15 @@
     return array[array.length - (back || 0) - 1];
   };
 
+  exports.some = (_ref = Array.prototype.some) != null ? _ref : function(fn) {
+    var e, _i, _len;
+    for (_i = 0, _len = this.length; _i < _len; _i++) {
+      e = this[_i];
+      if (fn(e)) {
+        return true;
+      }
+    }
+    return false;
+  };
+
 }).call(this);
diff --git a/lib/coffee-script/nodes.js b/lib/coffee-script/nodes.js
index 799b68eb47..9b2b43c879 100644
--- a/lib/coffee-script/nodes.js
+++ b/lib/coffee-script/nodes.js
@@ -1,6 +1,6 @@
 // Generated by CoffeeScript 1.3.3
 (function() {
-  var Access, Arr, Assign, Base, Block, Call, Class, Closure, Code, Comment, Existence, Extends, For, IDENTIFIER, IDENTIFIER_STR, IS_STRING, If, In, Index, LEVEL_ACCESS, LEVEL_COND, LEVEL_LIST, LEVEL_OP, LEVEL_PAREN, LEVEL_TOP, Literal, METHOD_DEF, NEGATE, NO, Obj, Op, Param, Parens, RESERVED, Range, Return, SIMPLENUM, STRICT_PROSCRIBED, Scope, Slice, Splat, Switch, TAB, THIS, Throw, Try, UTILITIES, Value, While, YES, compact, del, ends, extend, flatten, last, merge, multident, starts, unfoldSoak, utility, _ref, _ref1,
+  var Access, Arr, Assign, Base, Block, Call, Class, Closure, Code, Comment, Existence, Extends, For, IDENTIFIER, IDENTIFIER_STR, IS_STRING, If, In, Index, LEVEL_ACCESS, LEVEL_COND, LEVEL_LIST, LEVEL_OP, LEVEL_PAREN, LEVEL_TOP, Literal, METHOD_DEF, NEGATE, NO, Obj, Op, Param, Parens, RESERVED, Range, Return, SIMPLENUM, STRICT_PROSCRIBED, Scope, Slice, Splat, Switch, TAB, THIS, Throw, Try, UTILITIES, Value, While, YES, compact, del, ends, extend, flatten, last, merge, multident, some, starts, unfoldSoak, utility, _ref, _ref1,
     __hasProp = {}.hasOwnProperty,
     __extends = function(child, parent) { for (var key in parent) { if (__hasProp.call(parent, key)) child[key] = parent[key]; } function ctor() { this.constructor = child; } ctor.prototype = parent.prototype; child.prototype = new ctor(); child.__super__ = parent.prototype; return child; },
     __indexOf = [].indexOf || function(item) { for (var i = 0, l = this.length; i < l; i++) { if (i in this && this[i] === item) return i; } return -1; };
@@ -9,7 +9,7 @@
 
   _ref = require('./lexer'), RESERVED = _ref.RESERVED, STRICT_PROSCRIBED = _ref.STRICT_PROSCRIBED;
 
-  _ref1 = require('./helpers'), compact = _ref1.compact, flatten = _ref1.flatten, extend = _ref1.extend, merge = _ref1.merge, del = _ref1.del, starts = _ref1.starts, ends = _ref1.ends, last = _ref1.last;
+  _ref1 = require('./helpers'), compact = _ref1.compact, flatten = _ref1.flatten, extend = _ref1.extend, merge = _ref1.merge, del = _ref1.del, starts = _ref1.starts, ends = _ref1.ends, last = _ref1.last, some = _ref1.some;
 
   exports.extend = extend;
 
@@ -1172,9 +1172,42 @@
     Obj.prototype.children = ['properties'];
 
     Obj.prototype.compileNode = function(o) {
-      var i, idt, indent, join, lastNoncom, node, obj, prop, propName, propNames, props, _i, _j, _len, _len1, _ref2;
+      var i, idt, indent, isDuplicate, join, lastNoncom, node, normalise, obj, prop, propName, propNames, props, _i, _j, _len, _len1, _ref2;
       props = this.properties;
       propNames = [];
+      normalise = function(s) {
+        switch (s[0]) {
+          case '"':
+            return s.slice(1, -1).replace(/\\"/g, '"');
+          case "'":
+            return s.slice(1, -1).replace(/\\'/g, "'");
+        }
+      };
+      isDuplicate = function(x) {
+        var mx;
+        mx = x.match(/^['"]/);
+        return function(y) {
+          var my;
+          if (y === x || +y === +x) {
+            return true;
+          }
+          my = y.match(/^['"]/);
+          if (mx && my) {
+            if (normalise(x) === normalise(y)) {
+              return true;
+            }
+          } else if (mx) {
+            if (y === x.slice(1, -1)) {
+              return true;
+            }
+          } else if (my) {
+            if (x === y.slice(1, -1)) {
+              return true;
+            }
+          }
+          return false;
+        };
+      };
       _ref2 = this.properties;
       for (_i = 0, _len = _ref2.length; _i < _len; _i++) {
         prop = _ref2[_i];
@@ -1183,7 +1216,7 @@
         }
         if (prop != null) {
           propName = prop.unwrapAll().value.toString();
-          if (__indexOf.call(propNames, propName) >= 0) {
+          if (some.call(propNames, isDuplicate(propName))) {
             throw SyntaxError("multiple object literal properties named \"" + propName + "\"");
           }
           propNames.push(propName);
diff --git a/src/helpers.coffee b/src/helpers.coffee
index 20916eafc5..924c055610 100644
--- a/src/helpers.coffee
+++ b/src/helpers.coffee
@@ -54,3 +54,8 @@ exports.del = (obj, key) ->
 
 # Gets the last item of an array(-like) object.
 exports.last = (array, back) -> array[array.length - (back or 0) - 1]
+
+# Typical Array::some
+exports.some = Array::some ? (fn) ->
+  return true for e in this when fn e
+  false
diff --git a/src/nodes.coffee b/src/nodes.coffee
index 1573ac55a5..5e96bae60c 100644
--- a/src/nodes.coffee
+++ b/src/nodes.coffee
@@ -7,7 +7,7 @@
 {RESERVED, STRICT_PROSCRIBED} = require './lexer'
 
 # Import the helpers we plan to use.
-{compact, flatten, extend, merge, del, starts, ends, last} = require './helpers'
+{compact, flatten, extend, merge, del, starts, ends, last, some} = require './helpers'
 
 exports.extend = extend  # for parser
 
@@ -802,11 +802,26 @@ exports.Obj = class Obj extends Base
   compileNode: (o) ->
     props = @properties
     propNames = []
+    normalise = (s) -> switch s[0]
+      when '"' then s[1...-1].replace /\\"/g, '"'
+      when "'" then s[1...-1].replace /\\'/g, "'"
+    isDuplicate = (x) ->
+      mx = x.match /^['"]/
+      (y) ->
+        return true if y is x or +y is +x
+        my = y.match /^['"]/
+        if mx and my
+          return true if normalise(x) is normalise y
+        else if mx
+          return true if y is x[1...-1]
+        else if my
+          return true if x is y[1...-1]
+        false
     for prop in @properties
       prop = prop.variable if prop.isComplex()
       if prop?
         propName = prop.unwrapAll().value.toString()
-        if propName in propNames
+        if some.call propNames, isDuplicate propName
           throw SyntaxError "multiple object literal properties named \"#{propName}\""
         propNames.push propName
     return (if @front then '({})' else '{}') unless props.length
diff --git a/test/strict.coffee b/test/strict.coffee
index 20894f16f8..1ca3a57b11 100644
--- a/test/strict.coffee
+++ b/test/strict.coffee
@@ -57,9 +57,23 @@ test "octal escape sequences prohibited", ->
 
 
 test "duplicate property definitions in object literals are prohibited", ->
-  strict 'o = {x:1,x:1}'
+  strict 'o = {x:1, x:1}'
   strict 'x = 1; o = {x, x: 2}'
 
+test "#2333: more duplicate property prohibitions", ->
+  strict '{a:0, "a":0}'
+  strict "{'a':0, a:0}"
+  strict '{\'a\':0, "a":0}'
+  strict '{0:0, 0x0:0}'
+  strict '{0:0, "\\x30":0}'
+  strict '{.1:0, 0.1:0}'
+  strict '{.1:0, 1e-1:0}'
+  strict '{100:0, 1e2:0}'
+  strict '{"\\0":0, "\\x00":0}'
+  strict 'a = 0; {a, "a":0}'
+  strictOk '{0:0, "0x0":0}'
+  strictOk '{"a":0, "\'a\'":0}'
+
 test "duplicate formal parameters are prohibited", ->
   nonce = {}