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falsy vs typeof
(version: 0)
Benchmark.js
Comparing performance of:
falsy vs typeof
Created:
7 years ago
by:
Guest
Go to the latest result
Script Preparation code:
let a = null let b = null
Tests:
falsy
let a = undefined let b = null if (a) console.log('-') if (b) console.log('-')
typeof
let a = undefined let b = null if (typeof a === 'undefined') console.log('-') if (typeof b === 'undefined') console.log('-')
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
falsy
typeof
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_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/134.0.0.0 Safari/537.36
Browser/OS:
Chrome 134 on Mac OS X 10.15.7
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Embed Benchmark Result
<iframe src="https://measurethat.net/Embed?id=592654" width="100%" height="500px"></iframe>
falsy
103.3M/s
typeof
249K/s
View exact numbers
Test name
Executions per second
✓
falsy
103,260,400 Ops/sec
typeof
248,565 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'll break down the provided benchmark and explain what's being tested, compared, and other considerations. **Benchmark Overview** The test compares two different approaches to handle falsy values in JavaScript. Falsy values are values that evaluate to `false` in a boolean context. **Test Case 1: "falsy"** In this test case, the script checks if `a` or `b` is falsy using an `if` statement: ```javascript let a = null; let b = null; if (a) console.log('-'); if (b) console.log('-'); ``` The script will execute the `console.log()` statements because both `a` and `b` are considered falsy values. **Pros and Cons** * Pros: Simple and straightforward approach. * Cons: This approach can lead to unexpected behavior if not handled carefully, as falsy values can cause issues in certain contexts (e.g., array methods). **Test Case 2: "typeof"** In this test case, the script uses the `typeof` operator to check if `a` or `b` is undefined: ```javascript let a = undefined; let b = null; if (typeof a === 'undefined') console.log('-'); if (typeof b === 'undefined') console.log('-'); ``` The `typeof` operator returns `'undefined'` for both `a` and `b`, so the script will not execute the `console.log()` statements. **Pros and Cons** * Pros: More explicit and safer way to check if a value is undefined. * Cons: May be slower due to the use of `typeof`. **Library Used** In this benchmark, no specific JavaScript library is used. However, the use of `console` suggests that the test is running in a browser environment with a console API. **Other Considerations** Both approaches have their trade-offs: * Using an `if` statement and checking for falsy values can lead to issues if not handled carefully. * Using the `typeof` operator provides more explicit and safer checks, but may be slower due to its overhead. **Alternatives** If you're looking for alternative ways to handle falsy values in JavaScript, here are a few options: 1. **Using the nullish coalescing operator (`??`)**: Introduced in ES2020, this operator returns the first operand if it's not null or undefined; otherwise, it returns the second operand. 2. **Using a custom function**: You can create a custom function that checks for falsy values and provides more control over the behavior. Here's an example of using the nullish coalescing operator: ```javascript let a = null; let b = null; let result = a ?? b; console.log(result); // Output: null ``` Keep in mind that these alternatives may have their own pros and cons, depending on your specific use case.
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