Sameness.js is a pure JavaScript object comparing library. It has the capability to check if objects a and b are:

• The same object (isSame)
• Identical objects (isIdentical)
• Equivalent objects (isEquivalent)
• b a subset of a (isSubset)

Sameness.js is exposed throug the Sameness variable.

Checks if a and b objects are the same object. As being the same meaning they both reffer to the same instance of an object.

var a = { p: 1 };
var b = { p: 1 };
var c = a;

Sameness.isSame(a, b); // false
Sameness.isSame(a, c); // true

Checks if a and b objects are identical objects. As being identical meaning they both have the same properties and data, even if they doesn't share the same instance or type. Very usefull for anonymous objects.

var a = { p1: 9, p2: [ 1, 2, 3, 4, 5 ] };
var b = { p1: 9, p2: [ 1, 2, 3, 4, 5 ] };
var c = { p1: 9, p2: [ 5, 4, 3, 2, 1 ] };

Sameness.isIdentical(a, b); // true
Sameness.isIdentical(b, c); // false

Checks if a and b objects are equivalent to eachother. As being equivalent meaning that they may not share identical structures but both have the same properties and data, even if its properties and array items aren't in the same sequence. Being equivalent mean a and b probably represents the same thing but each one was generated differently.

var a = { p1: 9, p2: [ 1, 2, 3, 4, 5 ] };
var b = { p1: 9, p2: [ 1, 2, 3, 4, 5 ] };
var c = { p1: 9, p2: [ 5, 4, 3, 2, 1 ] };
var d = { p1: [ 5, 4, 3, 2, 1 ], p2: 9 };
var e = { p2: [ 5, 4, 3, 2, 1 ], p1: 9, p3: [] };

Sameness.isEquivalent(a, b); // true
Sameness.isEquivalent(b, c); // true
Sameness.isEquivalent(c, d); // true
Sameness.isEquivalent(d, e); // false

Cheks if b object is a subset of a object. As being a subset meaning all its properties and its data are completelly covered by the superset, but not meaning reciprocal is true.

var a = { p1: 9, p2: [ 1, 2, 3, 4, 5, 6, 7 ], p3: "z", p4: { p5: [] } };
var b = { p1: 9, p2: [ 1, 2, 3, 4, 5 ], p3: "z" };
var c = { p1: 9, p2: [ 5, 4, 3, 2, 1 ] };

Sameness.isSubset(a, b); // true
Sameness.isSubset(b, c); // true
Sameness.isSubset(a, c); // true
Sameness.isSubset(b, a); // false