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optimized isEqual function, 30x faster on integers #2179

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optimized isEqual function, 30x faster on integers #2179

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ee0ca0d
optimized isEqual
May 16, 2015
37eef9d
fixed performance problem with 0
May 16, 2015
ebc7bea
optimized NaN case
May 16, 2015
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13 changes: 7 additions & 6 deletions underscore.js
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Original file line number Diff line number Diff line change
Expand Up @@ -1110,11 +1110,6 @@

// Internal recursive comparison function for `isEqual`.
var eq = function(a, b, aStack, bStack) {
// Identical objects are equal. `0 === -0`, but they aren't identical.
// See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
if (a === b) return a !== 0 || 1 / a === 1 / b;
// A strict comparison is necessary because `null == undefined`.
if (a == null || b == null) return a === b;
// Unwrap any wrapped objects.
if (a instanceof _) a = a._wrapped;
if (b instanceof _) b = b._wrapped;
Expand Down Expand Up @@ -1203,7 +1198,13 @@

// Perform a deep comparison to check if two objects are equal.
_.isEqual = function(a, b) {
return eq(a, b);
// Identical objects are equal. `0 === -0`, but they aren't identical.
// See the [Harmony `egal` proposal](http://wiki.ecmascript.org/doku.php?id=harmony:egal).
if (a === b) return a !== 0 || 1 / a === 1 / b;
var typeA = typeof a;
if( typeA != typeof b ) return false;
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Unfortunately, types aren't enough since _.isEqual('test', new String('test')) === true.

if( typeA == 'object' ) return a && b ? eq( a, b ) : a === b;
return a != a ? b != b : a === b;
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You can't move this code so [NaN] == [NaN] (recursive cases)

};

// Is a given array, string, or object empty?
Expand Down