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checks if object has any key - Object.keys vs for key in 2
(version: 0)
Comparing performance of:
Object.keys vs for key .. in
Created:
3 years ago
by:
Registered User
Go to the latest result
Script Preparation code:
var obj = {} new Array(1000).map((item, index) => { obj[index] = index })
Tests:
Object.keys
!!Object.keys(obj).length
for key .. in
for(let key in obj){ return true; } return false
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
Object.keys
for key .. in
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
one year ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:139.0) Gecko/20100101 Firefox/139.0
Browser/OS:
Firefox 139 on Mac OS X 10.15
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<iframe src="https://measurethat.net/Embed?id=606463" width="100%" height="500px"></iframe>
Object.keys
78.6M/s
for key .. in
39.5M/s
View exact numbers
Test name
Executions per second
✓
Object.keys
78,585,144 Ops/sec
for key .. in
39,456,268 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the world of MeasureThat.net and understand what's being tested in this specific benchmark. **Benchmark Definition** The provided JSON defines two microbenchmarks: 1. **"checks if object has any key - Object.keys vs for key in 2"`** This benchmark compares two approaches to check if an object has any keys: * `Object.keys(obj).length`: Uses the `Object.keys()` method to get an array of the object's own enumerable property names, and then checks the length of that array. * `for (let key in obj) { return true; } return false;`: Uses a traditional `for...in` loop to iterate over the object's properties and returns `true` as soon as it encounters a property, or `false` if no properties are found. **Options Compared** The two approaches differ in their syntax, performance, and potential pitfalls: * **Object.keys()**: This method is more concise and modern. It uses a V8-specific internal function to iterate over the object's properties. The trade-off is that it requires JavaScript engines to support this method (most do). * **for...in loop**: This approach is more traditional and widely supported across older browsers and environments. However, it can be slower and less efficient than `Object.keys()`. **Pros and Cons** **Object.keys():** Pros: * Concise and readable syntax * Faster execution due to V8-specific optimization Cons: * May not work in older browsers or environments that don't support this method (e.g., Internet Explorer 11) **for...in loop:** Pros: * Widely supported across older browsers and environments * Can be useful for learning and debugging purposes Cons: * Less efficient due to the need to explicitly check for property existence * Potentially slower execution **Other Considerations** * Both approaches assume that the object has at least one property. If the object is empty, `Object.keys()` will return an empty array, while the `for...in` loop will not execute. * In modern JavaScript engines, `Object.keys()` is generally faster and more efficient than the `for...in` loop. **Library Usage** There doesn't seem to be any external libraries used in this benchmark. The two approaches rely solely on built-in JavaScript features. **Special JS Features or Syntax** None mentioned in this specific benchmark. However, it's worth noting that MeasureThat.net may use special JavaScript features or syntax to optimize performance or ensure compatibility across different browsers and environments. **Other Alternatives** For similar benchmarks, you might see other approaches such as: * Using `hasOwnProperty()` instead of `Object.keys()` * Comparing with regular expressions * Using a custom function to check for property existence These alternatives would depend on the specific requirements and constraints of the benchmark.
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