axios-date-transformer

axios-date-transformer

An Axios transformer for seamlessly converting ISO 8601 formatted date strings with millisecond precision to JavaScript Date objects. Simplify handling of Date objects in JSON responses with this lightweight utility.

Installation

npm install axios-date-transformer

or

yarn add axios-date-transformer

or

bun i axios-date-transformer

Usage

Creating a new axios instance

import { createAxiosDateTransformer } from 'axios-date-transformer';

// Create an Axios instance with the date transformer
const axiosInstance = createAxiosDateTransformer({
    baseURL: 'https://example.org',
});

// Use axiosInstance for your requests
axiosInstance
    .get('/api/data')
    .then(response => {
        // Date strings in the response data are automatically converted to Date objects
        console.log(response.data);
    }).catch(error => {
        console.error(error);
    });

Adding the transformer to an already existing instance of axios

import { addAxiosDateTransformer } from 'axios-date-transformer';

// Create an Axios instance with the date transformer
const axiosInstance = axios.create({
    baseURL: 'https://example.org',
});
const axiosWithTransformer = addAxiosDateTransformer(axiosInstance);

// Use axiosInstance for your requests
axiosWithTransformer
    .get('/api/data')
    .then(response => {
        // Date strings in the response data are automatically converted to Date objects
        console.log(response.data);
    }).catch(error => {
        console.error(error);
    });

Using the allowlist Feature

The allowlist feature allows you to specify which fields in the response should be converted to Date objects. This option is useful when only certain fields need to be treated as dates, and it prevents unintended transformations of other fields that match the ISO 8601 date format.

import { createAxiosDateTransformer } from 'axios-date-transformer';

// Create an Axios instance with the date transformer and an allowlist
const axiosInstance = createAxiosDateTransformer({
    baseURL: 'https://example.org',
    allowlist: ['createdAt', 'updatedAt'], // Only convert these fields to Date objects
});

axiosInstance.get('/api/data').then(response => {
    console.log(response.data);
});

Default Behavior without the allowlist Option

If no allowlist is specified, all fields matching the ISO 8601 date format (e.g., YYYY-MM-DDTHH:mm:ss.sssZ) will be converted to Date objects. This can lead to unintended conversions for fields that look like dates but are actually strings meant to be used as IDs, usernames, or other non-date fields.

Potential Issue without allowlist

If you have fields that visually match the date format but are not intended to be Date objects, those fields will also be transformed. For example:

{
  "username": "1980-01-25T00:00:00Z",
  "createdAt": "2023-09-28T12:00:00Z"
}

In the above response, username is likely meant to be a string, but the transformer will convert it to a Date object, causing unexpected behavior in your application.

Acknowledgment

Thanks to @OlliL for highlighting this potential issue in issue #11.

Contributing

If you find a bug or have an enhancement suggestion, feel free to open an issue or submit a pull request. Contributions are welcome!

License

This project is licensed under the MIT License - see the LICENSE file for details.