Benchmark: create map first and find many vs array find many

Script Preparation code:

var arr = Array.from({length: 1000000}).map((_,i) => ({id: i}));
var arrMap =  new Map(arr.entries());
function idGen() {
  return Math.floor(Math.random() * 1000000) % 1000000
}

Tests:

array to map and find many
const arrToMap = new Map(arr.entries()); const id = idGen() arrToMap.get(id)
array find
const id = idGen() arr.find((item) => item.id ==id)
map find
const id = idGen() arrMap.get(id)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
array to map and find many
array find
map find

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark definition and test cases.

**Benchmark Definition**

The benchmark definition is a JSON object that contains information about the test case, including its name, description, script preparation code, and HTML preparation code (which is empty in this case). The main difference between two approaches to find an element in an array:

*   **Creating a Map first and finding many**: This approach creates a new Map from the entries of an array. Then, it generates a random id using `idGen()`, retrieves a value from the map using that id (`arrMap.get(id)`), and repeats this process for 1000000 iterations.
*   **Array find**: In this case, the test is to simply find an element in the generated array with a given ID.

**Options Compared**

The main options being compared here are:

1.  Creating a Map from an array (`arrMap.get(id)`), where the map's key is used as the id.
2.  Using `Array.prototype.find()` method directly on the array, which searches for an element that matches the given condition.

**Pros and Cons**

Here are some pros and cons of these different approaches:

*   **Creating a Map First and Finding Many**:
    *   Pros: It provides faster lookup times since map lookups have an average time complexity of O(1), whereas array lookups in JavaScript can be slower (O(n)).
    *   Cons: Maps require additional memory to store the entries, especially for large arrays. Also, it requires more code and might not be a common operation.
*   **Array Find**:
    *   Pros: It's straightforward and easy to understand, requiring minimal modifications to your existing codebase.
    *   Cons: The array's size grows linearly with each element, making this approach less efficient for large datasets. Moreover, it involves a full iteration through the array.

**Library**

There is no library explicitly mentioned in this benchmark definition, however, `Array.from()` and `Map` are built-in JavaScript objects used here. However, some libraries like Lodash (`_`) might provide optimized versions of these operations or offer additional functionalities that simplify your codebase:

```javascript
import _ from 'lodash';

// Using _.find() for more complex condition checks
const result = _.find(arr, (item) => item.id === id);
```

**Special JS Feature**

In this benchmark definition, there are no special JavaScript features mentioned.

Related benchmarks:

create map first and find many vs array find many (version: 0)

Comparing performance of: array to map and find many vs array find vs map find

Created: 3 years ago by: Guest

Jump to the latest result

array to map and find many

array find

map find

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):