Toggle navigation
MeasureThat
.net
Create a benchmark
Tools
Feedback
Feature Requests
FAQ
Register
Log In
'value === undefined' VS 'typeof value === "undefined"' when value is defined
(version: 0)
Benchmark.js
Comparing performance of:
value === undefined vs typeof value === "undefined"
Created:
6 years ago
by:
Guest
Go to the latest result
Script Preparation code:
var value = undefined;
Tests:
value === undefined
value === undefined
typeof value === "undefined"
typeof value === "undefined"
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
Fork
Test case name
Result
value === undefined
typeof value === "undefined"
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
2 years ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36
Browser/OS:
Chrome 126 on Mac OS X 10.15.7
View result in a separate tab
Embed
Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=534095" width="100%" height="500px"></iframe>
typeof value === "undefined"
28.5M/s
value === undefined
10.8M/s
View exact numbers
Test name
Executions per second
✓
typeof value === "undefined"
28,515,884 Ops/sec
value === undefined
10,799,074 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's break down the provided JSON and explain what is being tested. **Benchmark Definition:** The benchmark definition compares two approaches to check if a variable `value` is `undefined`. The two approaches are: 1. `value === undefined` 2. `typeof value === "undefined"` These two approaches are often used interchangeably, but they have some subtle differences. **Approach 1: `value === undefined`** This approach uses the triple equals operator (`===`) to compare the value of `value` with `undefined`. This method is considered more concise and easier to read. However, it has a potential performance overhead due to the language's parsing mechanism. **Pros:** More concise, easier to read. **Cons:** Potential performance overhead due to parsing. **Approach 2: `typeof value === "undefined"`** This approach uses the `typeof` operator to check the type of `value`. If `value` is `undefined`, then `typeof value` will return `"undefined"`. This method can be slightly faster than the first approach, as it avoids the parsing overhead. **Pros:** Potential performance improvement due to avoidance of parsing. **Cons:** More verbose, less concise. **Library and special features:** There are no libraries or special features mentioned in the provided JSON. The benchmark only uses built-in JavaScript operators (`===`, `typeof`). **Other alternatives:** If you wanted to compare these two approaches in a different way, here are some alternative methods: * Using `==` instead of `===` for comparison * Using `value === null` or `value === undefined` (instead of `typeof value === "undefined"`) * Using a library like Lodash's `isEqual` function to compare the two expressions * Using a transpiler like Babel to compile the JavaScript code and then comparing the results However, these alternatives are not part of the original benchmark definition. **Benchmark preparation code:** The script preparation code is: ```javascript var value = undefined; ``` This sets the `value` variable to `undefined`, which is used as the input for both test cases. The HTML preparation code is empty (`null`), indicating that no additional setup is required for the benchmark. **Test cases:** There are two individual test cases: 1. "value === undefined" 2. "typeof value === \"undefined\"" Each test case measures the execution time of its respective approach using the `ExecutionsPerSecond` metric. The latest benchmark result shows the performance comparison between the two approaches on a Chrome 126 browser running on a Mac OS X 10.15.7 system. The results suggest that Approach 2 (`typeof value === "undefined"`) is slightly faster than Approach 1 (`value === undefined`).
Related benchmarks
Typeof x === 'undefined' vs x === undefined (test without syntax error)
typeof number vs not typeof undefined vs undefined
Comments
Confirm delete:
Do you really want to delete benchmark?