Скачать или смотреть How to Map Data to a New Array with Specific Fields and Values

Transforming arrays in JavaScript: Learn how to map data to a new array with specific fields, values, and daily object addition based on a date range.
---
This video is based on the question https://stackoverflow.com/q/72870668/ asked by the user 'Jakub' ( https://stackoverflow.com/u/7882685/ ) and on the answer https://stackoverflow.com/a/72871731/ provided by the user 'danh' ( https://stackoverflow.com/u/294949/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to map data to a new array with specific fields and values and add a single object per day based on a range of dates

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mapping Data to a New Array with Specific Fields and Values in JavaScript

When working with arrays in JavaScript, particularly when data is structured as objects with multiple properties, it can sometimes be a challenge to map that data to a new format that adheres to specific requirements. One such situation arises when you need to filter a series of objects based on a given range of dates, while ensuring that the data structure reflects these changes.

In this guide, we'll tackle how to map an array of objects to a new array. Each object in the resulting array will contain specific fields, values, and consolidate data based on given dates. Let's dive into the problem, understand the provided data set, and explore the solution step-by-step.

Understanding the Data Structure

We start with an array of objects, each of which represents a study with the following properties:

id: Unique identifier for the study

studyId: Identifier for the study type

siteId: Identifier for the site having that study

statusType: Status of the study (e.g., INCOMPLETE, REJECTED)

statusFrom: Start date of the status

statusTo: End date of the status

Here's a snippet of the initial data:

[[See Video to Reveal this Text or Code Snippet]]

The Date Range

We also have a range of specific dates formatted in ISO format, from which we will derive our new data representation.

[[See Video to Reveal this Text or Code Snippet]]

The Goal

The challenge is to create a new array of objects that contain:

A specific day from the date range

Total counts of how many objects match a particular statusType for the corresponding day

Solution Steps

In order to accomplish the mapping, we will break down our implementation into logical parts:

Step 1: Prepare Input Objects

First, we will convert the statusFrom and statusTo values to time in milliseconds for easier comparisons.

[[See Video to Reveal this Text or Code Snippet]]

Step 2: Format the Dates

Next, we convert the dates into a format suitable for comparison, while also extracting just the date part for our resulting objects.

[[See Video to Reveal this Text or Code Snippet]]

Step 3: Matching Studies to Dates

Using a loop, we will filter out the studies that fall into the range defined by each date. We will build a unique identifier (studyId-day) to ensure each combination is stored correctly.

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By following these steps, we created a new array mapping all required properties, ensuring we correctly managed overlapping statuses while adhering to the given restrictions. This approach avoids the use of traditional loops, leveraging modern JavaScript methods like map, filter, and forEach to maintain clean, readable code.

This method of dynamically creating arrays based on date ranges can be useful in various applications, such as analytics, reporting, and data visualization. Happy coding!