let obj = {}
for (let i = 0; i < 1000; i++) {
obj = {obj, [i]: (i || 0) + 1}
}
const obj = {}
for (let i = 0; i < 1000; i++) {
obj[i] = (obj[i] || 0) + 1
}
const map = new Map()
for (let i = 0; i < 1000; i++) {
map.set(i, (map.get(i) || 0) + 1)
}
--enable-precise-memory-info
flag.
Test case name | Result |
---|---|
object update with spread operator | |
object update with indexing | |
map update |
Test name | Executions per second |
---|---|
object update with spread operator | 2739.1 Ops/sec |
object update with indexing | 53870.3 Ops/sec |
map update | 24568.5 Ops/sec |
Benchmark Overview
The provided benchmark measures the performance of three different approaches to update an object in JavaScript: using the spread operator (object spread
), indexing (object index
), and using a Map
data structure (map set
). The benchmark aims to compare the execution speed of these approaches.
Options Compared
...
) to update an object by spreading its current properties into a new object, and then overwriting the existing properties with the new ones.obj[i] = ...
) to update an object's property at a specific key (i
).Map
data structure to store key-value pairs, and updates the value associated with a given key.Pros and Cons of Each Approach
Library and Syntax Used
In the provided benchmark, no specific libraries are used beyond the standard JavaScript features. However, it is worth noting that some implementations of Map
may rely on non-standard browser features, such as Object.create()
or Array.prototype.indexOf()
, to provide efficient updates.
Special JS Feature/Syntax
The spread operator (...
) is a relatively recent addition to JavaScript, introduced in ECMAScript 2018 (ES10). It allows creating new objects by spreading an existing object's properties into a new object. The indexing approach (obj[i] = ...
) uses the Array.prototype.length
property to access array-like objects.
Other Alternatives
If you need to update an object, other alternatives to these approaches include:
Object.assign()
: A more traditional way of updating an object by copying properties from another object.assignIn()
or merge()
: Provides more features and flexibility for updating objects.currying
or memoization
: Can lead to more efficient updates, especially in complex scenarios.For Map-based data structures, consider using libraries like Lodash's mapSet()
or mapDelete()
, which provide additional functionality beyond the basic Map
API.
When choosing an approach, consider factors such as:
Ultimately, the best approach depends on your specific use case and personal preference.