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for-in vs object.keys (1)
(version: 0)
Comparing performance of:
for-in vs Object.keys
Created:
4 years ago
by:
Guest
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Script Preparation code:
var obj = { quitMin: 'mod+q', addTab: 'mod+t', addPrivateTab: 'shift+mod+n', duplicateTab: 'shift+mod+d', addTask: 'mod+n', toggleTasks: 'shift+mod+e', goBack: 'mod+left', goForward: 'mod+right', enterEditMode: ['mod+l', 'mod+k'], runShortcut: 'mod+e', completeSearchbar: 'mod+enter', closeTab: 'mod+w', restoreTab: 'shift+mod+t', gotoFirstTab: 'shift+mod+9', gotoLastTab: 'mod+9', addToFavorites: 'mod+d', showBookmarks: 'shift+mod+b', toggleReaderView: 'shift+mod+r', switchToNextTab: ['option+mod+right', 'ctrl+tab', 'shift+mod+pagedown'], switchToPreviousTab: ['option+mod+left', 'shift+ctrl+tab', 'shift+mod+pageup'], moveTabLeft: 'option+mod+shift+left', moveTabRight: 'option+mod+shift+right', switchToNextTask: 'mod+]', switchToPreviousTask: 'mod+[', closeAllTabs: 'shift+mod+w', reload: ['mod+r', 'f5'], reloadIgnoringCache: 'mod+f5', showMenu: 'ctrl+m', followLink: 'mod+enter', fillPassword: 'mod+\\', toggleTabAudio: 'shift+mod+m', showHistory: 'shift+mod+h' };
Tests:
for-in
for (var i=100; i > 0; i--) { for (var key in obj) { console.log(key); } }
Object.keys
for (var i=100; i > 0; i--) { Object.keys(obj).forEach(key => console.log(key)); }
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
for-in
Object.keys
Fastest:
N/A
Slowest:
N/A
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Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
Let's dive into the explanation of the benchmark. **Benchmark Purpose:** The purpose of this benchmark is to compare the performance of two approaches for iterating over an object's properties in JavaScript: the traditional `for-in` loop and the newer `Object.keys()` method. **Options Compared:** 1. **For-in Loop**: This is a traditional loop that uses the `in` operator to iterate over an object's properties. 2. **Object.keys() Method**: This method returns an array of strings representing the enumerable property names of an object. **Pros and Cons of Each Approach:** * **For-in Loop**: + Pros: It can be used for iterating over both own and inherited properties (using `in` operator), which might be useful in certain scenarios. + Cons: It is generally slower than other methods, as it uses a separate mechanism to iterate over the object's properties. Additionally, it has some gotchas, such as returning undefined values when iterating over prototypes. * **Object.keys() Method**: + Pros: It is faster and more modern, as it uses an optimized algorithm for array iteration. + Cons: It only returns enumerable property names, which means non-enumerable properties (such as those with a `symbol` value) are not included in the iteration. **Library Used:** None **Special JavaScript Features/Syntax:** The benchmark does not use any special JavaScript features or syntax. However, it is worth noting that the `Object.keys()` method was introduced in ECMAScript 2015 (ES6), which might be relevant to some developers. **Other Considerations:** * The benchmark assumes that the object being iterated over has a specific structure and properties, as defined in the `obj` variable. * The benchmark does not account for differences in browser behavior or optimizations between different JavaScript engines. **Alternatives:** If you want to compare other approaches for iterating over an object's properties, you could consider using: 1. **Array.prototype.forEach()**: This method is similar to `Object.keys()` but provides a more flexible way of iterating over arrays. 2. **for...of Loop**: This loop is newer and provides a more modern way of iterating over iterable objects, including arrays and objects. In summary, this benchmark compares the performance of two approaches for iterating over an object's properties: the traditional `for-in` loop and the newer `Object.keys()` method. The results can help developers understand which approach is faster and more suitable for their use cases.
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