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Map .has() vs .get()
(version: 3)
Benchmark.js
This is to compare the cost of this pattern ```if (map.has(key)) func1(map.get(key))``` v/s ```const v = map.get(key); if (v) func1(v);```
Comparing performance of:
.has() and .get() vs .get() only
Created:
8 years ago
by:
Registered User
Go to the latest result
Script Preparation code:
function noop() {} map = new Map(); keys = []; for (let i = 0; i < 10000; i++) { const k = new Number(i); keys.push(k); if (k % 2 !== 0) map.set(k, i); }
Tests:
.has() and .get()
keys.forEach(k => { if (map.has(k)) noop(map.get(k)); })
.get() only
keys.forEach(k => { const v = map.get(k); if (v) noop(v); })
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
.has() and .get()
.get() only
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
8 months ago
)
User agent:
Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:146.0) Gecko/20100101 Firefox/146.0
Browser/OS:
Firefox 146 on Windows
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=623334" width="100%" height="500px"></iframe>
.get() only
2K/s
.has() and .get()
1K/s
View exact numbers
Test name
Executions per second
✓
.get() only
1,640 Ops/sec
.has() and .get()
1,259 Ops/sec
Autogenerated LLM Summary
(model
gemma2:9b
, generated one year ago):
This benchmark on MeasureThat.net compares two ways to check if a key exists in a `Map` object in JavaScript and then execute a function with the associated value: **Approach 1: `.has()` and `.get()`** ```javascript keys.forEach(k => { if (map.has(k)) noop(map.get(k)); }); ``` * **Explanation:** This approach first uses the `.has()` method to check if the key exists in the `Map`. If it does, the `.get()` method is called to retrieve the associated value, which is then passed to the `noop()` function. **Approach 2: `.get()` only** ```javascript keys.forEach(k => { const v = map.get(k); if (v) noop(v); }); ``` * **Explanation:** This approach directly uses the `.get()` method to retrieve the value associated with each key. If the key exists, `map.get(k)` returns the value; otherwise, it returns `undefined`. The `if (v)` statement then checks if a value was retrieved (not undefined), and only executes `noop(v)` if so. **Pros and Cons:** * **Approach 1: `.has()` and `.get()`** * **Pro:** Potentially more readable, as it explicitly shows the check for key existence before retrieving the value. * **Con:** Might be slightly slower due to the extra method call (`map.has(k)`). * **Approach 2: `.get()` only** * **Pro:** Potentially faster, as it avoids an extra method call. * **Con:** Less explicit about checking for key existence; the `if (v)` statement might be less clear to some readers. **Other Considerations:** * The benchmark results may vary depending on factors such as the size of the map, the specific browser and JavaScript engine being used, and the hardware configuration. * In most real-world scenarios, the performance difference between these two approaches would likely be negligible. Let me know if you'd like to explore other benchmarking concepts or have more questions!
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