var foo = {};
var sym = Symbol("key");
var str = "ke";
foo[sym] = 1;
foo[str + "y"] = 1;
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
Symbol | |
String |
Test name | Executions per second |
---|---|
Symbol | 8152597.5 Ops/sec |
String | 5555626.5 Ops/sec |
Let's break down the provided JSON and explain what is being tested.
What is being tested?
The test case measures the performance difference between using a Symbol
property versus a string literal ("ke"
) when accessing an object's property. Specifically, it tests how fast each approach is to set a value of 1 on an object foo
.
Options compared:
Two options are being compared:
Symbol
as a property name, created using the Symbol()
function."ke"
) as a property name.Pros and Cons of each approach:
Library usage:
The Symbol
property is being used, which is a built-in JavaScript language feature introduced in ECMAScript 2015. The purpose of using Symbol
is to create unique and non-overlapping property names.
Special JS feature or syntax:
This test case uses the Symbol()
function to create a symbol at runtime, which is a special syntax for creating unique symbols. This allows for more efficient and collision-free property access.
Benchmark preparation code:
The script preparation code creates an object foo
and defines two variables: sym
(a symbol) and str
(the string literal "ke"
). The final line of the code sets a value of 1 on each object using the corresponding variable name.
Other alternatives:
If you wanted to test alternative approaches, you could consider:
in
operator vs. bracket notation ([]
) for accessing object properties.Note that these alternatives would require modifying the benchmark code and may not provide comparable results due to differences in syntax and semantics.