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// Copyright 2012 The Closure Library Authors. All Rights Reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//      http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS-IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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/**
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 * @fileoverview A labs location for functions destined for Closure's
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 * {@code goog.object} namespace.
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 * @author [email protected] (Chris Henry)
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 */
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goog.provide('goog.labs.object');
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/**
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 * Whether two values are not observably distinguishable. This
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 * correctly detects that 0 is not the same as -0 and two NaNs are
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 * practically equivalent.
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 *
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 * The implementation is as suggested by harmony:egal proposal.
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 *
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 * @param {*} v The first value to compare.
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 * @param {*} v2 The second value to compare.
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 * @return {boolean} Whether two values are not observably distinguishable.
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 * @see http://wiki.ecmascript.org/doku.php?id=harmony:egal
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 */
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goog.labs.object.is = function(v, v2) {
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  if (v === v2) {
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    // 0 === -0, but they are not identical.
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    // We need the cast because the compiler requires that v2 is a
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    // number (although 1/v2 works with non-number). We cast to ? to
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    // stop the compiler from type-checking this statement.
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    return v !== 0 || 1 / v === 1 / /** @type {?} */ (v2);
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  }
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  // NaN is non-reflexive: NaN !== NaN, although they are identical.
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  return v !== v && v2 !== v2;
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};
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