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Option chaining and typeof 2
(version: 0)
Comparing performance of:
Optional chaining, not null vs Explicit null check, not null vs Optional chaining, null vs Explicit null check, null
Created:
3 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
window._x = { y: 4 }; window._z = null;
Tests:
Optional chaining, not null
let a = typeof (_x === null || _x === void 0 ? void 0 : _x.y) === `number`;
Explicit null check, not null
let a = _x != null && typeof _x.y === `number`;
Optional chaining, null
let a = typeof (_z === null || _z === void 0 ? void 0 : _z.y) === `number`;
Explicit null check, null
let a = _z != null && typeof _z.y === `number`;
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (4)
Previous results
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Test case name
Result
Optional chaining, not null
Explicit null check, not null
Optional chaining, null
Explicit null check, null
Fastest:
N/A
Slowest:
N/A
Latest run results:
No previous run results
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
**Overview of the Benchmark** The provided JSON represents a JavaScript microbenchmark that tests the performance of two different approaches to check if an object has a certain property and its value is a specific type. **Benchmark Definition** The benchmark definition is: ``` let a = typeof (_x === null || _x === void 0 ? void 0 : _x.y) === `number`; ``` This line checks if the property `y` of an object `_x` exists and its value is a string that equals "number". The optional chaining operator (`?.`) is used to access the `y` property without throwing an error if it doesn't exist. There are four test cases: 1. **Optional Chaining, Not Null**: Checks if the `y` property of `_x` exists and its value is a string that equals "number". 2. **Explicit Null Check, Not Null**: Uses an explicit null check (`_x != null`) to access the `y` property. 3. **Optional Chaining, Null**: Checks if the `y` property of an object with `null` value exists and its value is a string that equals "number". 4. **Explicit Null Check, Null**: Uses an explicit null check (`_z != null`) to access the `y` property. **Libraries and Special Features** There is no library used in this benchmark. However, there are some special features: * The optional chaining operator (`?.`) was introduced in JavaScript with the release of ECMAScript 2020 (ES2020). It allows you to access nested properties without throwing an error if a null or undefined value is encountered. * The `void 0` expression is used to achieve null coalescing, which is also a new feature introduced in ES2020. **Approach Comparison** The benchmark compares the performance of two approaches: 1. **Optional Chaining**: Uses the optional chaining operator (`?.`) to access nested properties without checking for null or undefined values. 2. **Explicit Null Check**: Uses explicit checks (`_x != null` or `_z != null`) to ensure that the object exists before accessing its properties. **Pros and Cons of Each Approach** * **Optional Chaining**: + Pros: More concise, readable code; avoids unnecessary checks. + Cons: May be slower due to the additional complexity introduced by the optional chaining operator. * **Explicit Null Check**: + Pros: Can be faster since it only checks for null or undefined values once. + Cons: Requires more code and can make the syntax less concise. **Other Considerations** * The benchmark uses Chrome 108 as the browser, which may affect the results due to differences in JavaScript engine optimizations between browsers. * The `DevicePlatform` and `OperatingSystem` fields are not relevant to the performance comparison but provide additional metadata about the test environment. * The `ExecutionsPerSecond` field provides a measure of the benchmark's execution frequency, which can be used to compare the performance across different browsers or versions. **Alternatives** Some possible alternatives to this benchmark could include: * Testing other ways to check for null or undefined values, such as using the `??` operator (nullish coalescing) or explicit checks with `in` operator. * Comparing the performance of optional chaining with explicit null checking in different browsers or versions. * Using a more comprehensive test suite that covers various use cases and edge scenarios.
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