var obj = {a:1}
obj instanceof Object
typeof obj === 'object' && obj !== null
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
instanceof | |
typeof |
Test name | Executions per second |
---|---|
instanceof | 4012716.0 Ops/sec |
typeof | 6658261.0 Ops/sec |
Let's break down the provided JSON and explain what is being tested, compared, and considered.
Benchmark Definition
The provided JSON represents a benchmark definition for comparing two approaches:
obj instanceof Object
typeof obj === 'object' && obj !== null
Both tests are designed to check if an object (obj
) is of type Object
using different methods: the instanceof
operator and a string comparison.
What's being tested?
In essence, these two tests aim to measure:
Object
: using the instanceof
operator or a string comparison with typeof
followed by a negation (obj !== null
).Options compared
The two options being compared are:
instanceof
operator: This operator checks if an object is of a specific class (in this case, Object
). It's a built-in JavaScript operator that returns true
if the object is an instance of the specified class and false
otherwise.typeof
and negation: This approach involves using typeof
to check if the object is of type 'object'
, followed by a negation (obj !== null
) to exclude null
values.Pros and Cons
instanceof
operator:typeof
and negation:obj !== null
) and may involve more overhead due to string comparison.Library usage
There is no library explicitly mentioned in the provided JSON. However, the typeof
operator uses a library called V8
(Chrome's JavaScript engine), which provides the implementation for this operator.
Special JS feature or syntax
The instanceof
operator is a built-in JavaScript feature that checks if an object is of a specific class. There are no special features or syntaxes mentioned in the provided JSON.
Other alternatives
Alternative approaches to checking if an object is of type Object
might include:
isPlainObject()
function.obj === Object.prototype && obj !== null
) or recursion.Map
, to store objects and then checking if an object is present in the map.Keep in mind that these alternatives might not be as efficient or straightforward as using the instanceof
operator or string comparison with typeof
and negation.