Comparison.md

Comparison of prior art

Constructor / Feature	lodash	underscore	ramda	jQuery	abused JSON	Object.clone
Undefined	===	===	===	===	!!!¹ / ===	===
Null	===	===	===	===	===	===
Boolean	===	===	===	===	===	===
Number	===	===	===	===	===	===
String	===	===	===	===	===	===
Function	XXX	XXX	===	===	!!!	===
Symbol	!!!	!!!	!!!	!!!	!!!	===
Array	!==	!==	!==	!==	!==²	!==
Object	!==	!==	!==	!==	!==²	!==
Date	!==	XXX	!==	===	XXX³	!==
RegExp	!==	XXX	!==	===	XXX	!==
TypedArray	!==	XXX	===	===	XXX	!==
Set	!==	XXX	===	===	XXX	!==
Map/WeakMap	!==	XXX	===	===	XXX	!==
Circular references	!==	!!!	!==	!!!	!!!	!==

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¹ if the primary argument is undefined, JSON.parse will throw, since it is no valid JSON ² cloned properties will only work for the simple types supported by JSON ³ Date will yield a string representation that can be parsed

• ===: same reference as incoming object
• !==: cloned reference with cloned properties
• XXX: wrong result
• !!!: error thrown

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Versions tested:

• lodash: 4.17.20
• underscore.deepclone: 0.1.3
• ramda: 0.27.1
• jQuery: 3.5.1
• JSON.stringify/.parse: Chrome 87