imagekit-javascript

ImageKit.io Javascript SDK

Javascript SDK for ImageKit provides URL generation for image & video resizing and provides an interface for file upload. This SDK is lightweight and has no dependency. You can also use this as an ES module.

ImageKit is complete media storage, optimization, and transformation solution that comes with an image and video CDN. It can be integrated with your existing infrastructure - storage like AWS S3, web servers, your CDN, and custom domain names, allowing you to deliver optimized images in minutes with minimal code changes.

Changelog

SDK Version 3.0.0

Breaking changes

1. Overlay syntax update

• In version 3.0.0, we've removed the old overlay syntax parameters for transformations, such as oi, ot, obg, and more. These parameters are deprecated and will start returning errors when used in URLs. Please migrate to the new layers syntax that supports overlay nesting, provides better positional control, and allows more transformations at the layer level. You can start with examples to learn quickly.
• You can migrate to the new layers syntax using the raw transformation parameter.

SDK Version 2.0.0

Breaking changes

1. Authentication Process Update:

• Previously, when using client side file upload, the SDK required the publicKey and authenticationEndpoint parameters during SDK initialization to fetch security parameters (signature, token, and expire).
• In version 2.0.0, we've updated the authentication process for the SDK. As a user of the SDK, you are now responsible for generating the security parameters (signature, token, and expire) yourself. This means you no longer need to provide the authenticationEndpoint. When using the SDK's upload method, make sure to pass these security parameters explicitly along with other upload options. For guidance on generating these security parameters, please refer to the documentation available here.

Installation

Using npm

Install imagekit-javascript

npm install imagekit-javascript --save
#or
yarn add imagekit-javascript

Now import ImageKit

import ImageKit from "imagekit-javascript"

// or
const ImageKit = require("imagekit-javascript")

Using CDN

You can download a specific version of this SDK from a global CDN.

https://unpkg.com/imagekit-javascript@1.3.0/dist/imagekit.min.js

For the latest version, remove the version number i.e.

https://unpkg.com/imagekit-javascript/dist/imagekit.min.js

Now load it using a <script> tag.

<script type="text/javascript" src="https://unpkg.com/imagekit-javascript/dist/imagekit.min.js"></script>

Initialization

urlEndpoint is required to use the SDK. You can get URL-endpoint from your ImageKit dashboard - https://imagekit.io/dashboard#url-endpoints

var imagekit = new ImageKit({
    urlEndpoint: "https://ik.imagekit.io/your_imagekit_id"
});    

publicKey parameter is required if you want to use the SDK for client-side file upload. You can get this parameter from the developer section in your ImageKit dashboard - https://imagekit.io/dashboard#developers

var imagekit = new ImageKit({
    publicKey: "your_public_api_key",
    urlEndpoint: "https://ik.imagekit.io/your_imagekit_id",
});    

Note: Do not include your Private Key in any client-side code, including this SDK or its initialization. If you pass the privateKey parameter while initializing this SDK, it throws an error

Demo Application

The fastest way to get started is by running the demo application in samples/sample-app folder. Follow these steps to run the application locally:

git clone https://github.com/imagekit-developer/imagekit-javascript.git

cd imagekit-javascript

Create a file .env using sample.env in the directory samples/sample-app and fill in your PRIVATE_KEY, PUBLIC_KEY and URL_ENDPOINT from your imageKit dashboard. SERVER_PORT must also be included as per the sample.env file.

Now start the sample application by running:

// Run it from the project root
yarn startSampleApp

Usage

You can use this SDK for URL generation and client-side file uploads.

URL Generation

1. Using image path and image hostname or endpoint

This method allows you to create an URL to access a file using the relative file path and the ImageKit URL endpoint (urlEndpoint). The file can be an image, video, or any other static file supported by ImageKit.

var imageURL = imagekit.url({
    path: "/default-image.jpg",
    urlEndpoint: "https://ik.imagekit.io/your_imagekit_id/endpoint/",
    transformation: [{
        "height": "300",
        "width": "400"
    }]
});

This results in a URL like

https://ik.imagekit.io/your_imagekit_id/endpoint/tr:h-300,w-400/default-image.jpg

2. Using full image URL

This method allows you to add transformation parameters to an absolute URL. For example, if you have configured a custom CNAME and have absolute asset URLs in your database or CMS, you will often need this.

var imageURL = imagekit.url({
    src: "https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg",
    transformation: [{
        "height": "300",
        "width": "400"
    }]
});

This results in a URL like

https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=h-300%2Cw-400

The .url() method accepts the following parameters

Option	Description
urlEndpoint	Optional. The base URL to be appended before the path of the image. If not specified, the URL Endpoint specified at the time of SDK initialization is used. For example, https://ik.imagekit.io/your_imagekit_id/endpoint/
path	Conditional. This is the path at which the image exists. For example, /path/to/image.jpg. Either the path or src parameter needs to be specified for URL generation.
src	Conditional. This is the complete URL of an image already mapped to ImageKit. For example, https://ik.imagekit.io/your_imagekit_id/endpoint/path/to/image.jpg. Either the path or src parameter needs to be specified for URL generation.
transformation	Optional. An array of objects specifying the transformation to be applied in the URL. The transformation name and the value should be specified as a key-value pair in the object. Different steps of a chained transformation can be specified as different objects of the array. The complete list of supported transformations in the SDK and some examples of using them are given later. If you use a transformation name that is not specified in the SDK, it gets applied as it is in the URL.
transformationPostion	Optional. The default value is path, which places the transformation string as a path parameter in the URL. It can also be specified as query, which adds the transformation string as the query parameter tr in the URL. If you use the src parameter to create the URL, then the transformation string is always added as a query parameter.
queryParameters	Optional. These are the other query parameters that you want to add to the final URL. These can be any query parameters and are not necessarily related to ImageKit. Especially useful if you want to add some versioning parameters to your URLs.

Examples of generating URLs

1. Chained Transformations as a query parameter

var imageURL = imagekit.url({
    path: "/default-image.jpg",
    urlEndpoint: "https://ik.imagekit.io/your_imagekit_id/endpoint/",
    transformation: [{
        "height": "300",
        "width": "400"
    }, {
        "rotation": 90
    }],
    transformationPosition: "query"
});

https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=h-300%2Cw-400%3Art-90

2. Sharpening and contrast transforms and a progressive JPG image

There are some transforms like Sharpening that can be added to the URL with or without any other value. To use such transforms without specifying a value, specify the value as "-" in the transformation object. Otherwise, specify the value that you want to be added to this transformation.

var imageURL = imagekit.url({
    src: "https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg",
    transformation: [{
        "format": "jpg",
        "progressive": "true",
        "effectSharpen": "-",
        "effectContrast": "1"
    }]
});

//Note that because `src` parameter was used, the transformation string gets added as a query parameter `tr`
https://ik.imagekit.io/your_imagekit_id/endpoint/default-image.jpg?tr=f-jpg%2Cpr-true%2Ce-sharpen%2Ce-contrast-1

3. Adding overlays

ImageKit.io enables you to apply overlays to images and videos using the raw parameter with the concept of layers. The raw parameter facilitates incorporating transformations directly in the URL. A layer is a distinct type of transformation that allows you to define an asset to serve as an overlay, along with its positioning and additional transformations.

Text as overlays

You can add any text string over a base video or image using a text layer (l-text).

For example:

var imageURL = imagekit.url({
    src: "https://ik.imagekit.io/your_imagekit_id/default-image.jpg",
    transformation: [{
        "width": 400,
        "height": 300
        "raw": "l-text,i-Imagekit,fs-50,l-end"
    }]
});

Sample Result URL

https://ik.imagekit.io/your_imagekit_id/tr:h-300,w-400,l-text,i-Imagekit,fs-50,l-end/default-image.jpg

Image as overlays

You can add an image over a base video or image using an image layer (l-image).

For example:

var imageURL = imagekit.url({
    src: "https://ik.imagekit.io/your_imagekit_id/default-image.jpg",
    transformation: [{
        "width": 400,
        "height": 300
        "raw": "l-image,i-default-image.jpg,w-100,b-10_CDDC39,l-end"
    }]
});

Sample Result URL

https://ik.imagekit.io/your_imagekit_id/tr:h-300,w-400,l-image,i-default-image.jpg,w-100,b-10_CDDC39,l-end/default-image.jpg

Solid color blocks as overlays

You can add solid color blocks over a base video or image using an image layer (l-image).

For example:

var imageURL = imagekit.url({
    src: "https://ik.imagekit.io/your_imagekit_id/img/sample-video.mp4",
    transformation: [{
        "width": 400,
        "height": 300
        "raw": "l-image,i-ik_canvas,bg-FF0000,w-300,h-100,l-end"
    }]
});

Sample Result URL

https://ik.imagekit.io/your_imagekit_id/tr:h-300,w-400,l-image,i-ik_canvas,bg-FF0000,w-300,h-100,l-end/img/sample-video.mp4

4. Arithmetic expressions in transformations

ImageKit allows use of arithmetic expressions in certain dimension and position-related parameters, making media transformations more flexible and dynamic.

For example:

var imageURL = imagekit.url({
    src: "https://ik.imagekit.io/your_imagekit_id/default-image.jpg",
    transformation: [{
        "width": "iw_div_4",
        "height": "ih_div_2",
        "border": "cw_mul_0.05_yellow"
    }]
});

Sample Result URL

https://ik.imagekit.io/your_imagekit_id/default-image.jpg?tr=w-iw_div_4,h-ih_div_2,b-cw_mul_0.05_yellow

List of supported transformations

See the complete list of transformations supported in ImageKit here. The SDK gives a name to each transformation parameter e.g. height for h and width for w parameter. It makes your code more readable. If the property does not match any of the following supported options, it is added as it is.

If you want to generate transformations in your application and add them to the URL as it is, use the raw parameter.

Supported Transformation Name	Translates to parameter
height	h
width	w
aspectRatio	ar
quality	q
crop	c
cropMode	cm
x	x
y	y
focus	fo
format	f
radius	r
background	bg
border	b
rotation	rt
blur	bl
named	n
progressive	pr
lossless	lo
trim	t
metadata	md
colorProfile	cp
defaultImage	di
dpr	dpr
effectSharpen	e-sharpen
effectUSM	e-usm
effectContrast	e-contrast
effectGray	e-grayscale
effectShadow	e-shadow
effectGradient	e-gradient
original	orig
raw	The string provided in raw will be added in the URL as it is.

File Upload

The SDK provides a simple interface using the .upload() method to upload files to the ImageKit Media Library.

The upload() method requires mandatory file and the fileName parameter. In addition, it accepts all the parameters supported by the ImageKit Upload API.

Also, before making an upload request, please ensure you have generated mandatory security parameters: signature, token, and expire. To generate these security parameters, refer to the documentation here. Obtain the parameters using a secure method and pass them, along with the mandatory file and fileName parameters, to the upload() method.

You can pass other parameters supported by the ImageKit upload API using the same parameter name as specified in the upload API documentation. For example, to specify tags for a file at the time of upload, use the tags parameter as specified in the documentation here.

Sample usage

<form action="#" onsubmit="upload()">
    <input type="file" id="file1" />
    <input type="submit" />
</form>
<script type="text/javascript" src="../dist/imagekit.js"></script>

<script>
    /*  
    SDK initialization
    */
    var imagekit = new ImageKit({
        publicKey: "your_public_api_key",
        urlEndpoint: "https://ik.imagekit.io/your_imagekit_id",
    });
    
    // Upload function internally uses the ImageKit.io javascript SDK
    function upload(data) {
        var file = document.getElementById("file1");

        // Using Callback Function
        imagekit.upload({
            file: file.files[0],
            fileName: "abc1.jpg",
            tags: ["tag1"],
            token: 'generated_token',
            signature: 'generated_signature',
            expire: 'generated_expire',
            extensions: [
                {
                    name: "aws-auto-tagging",
                    minConfidence: 80,
                    maxTags: 10
                }
            ],
            transformation: {
                pre: 'l-text,i-Imagekit,fs-50,l-end',
                post: [
                    {
                        type: 'transformation',
                        value: 'w-100'
                    }
                ]
            }
        }, function(err, result) {
            console.log(result);
        })

        // Using Promises
        imagekit.upload({
            file: file.files[0],
            fileName: "abc1.jpg",
            tags: ["tag1"],
            token: 'generated_token',
            signature: 'generated_signature',
            expire: 'generated_expire',
            extensions: [
                {
                    name: "aws-auto-tagging",
                    minConfidence: 80,
                    maxTags: 10
                }
            ],
            transformation: {
                pre: 'l-text,i-Imagekit,fs-50,l-end',
                post: [
                    {
                        type: 'transformation',
                        value: 'w-100'
                    }
                ]
            }
        }).then(result => {
            console.log(result);
        }).then(error => {
            console.log(error);
        })
    }
</script>

If the upload succeeds, err will be null, and the result will be the same as what is received from ImageKit's servers. If the upload fails, err will be the same as what is received from ImageKit's servers, and the result will be null.

Tracking upload progress using custom XMLHttpRequest

You can use a custom XMLHttpRequest object as the following to bind progress or any other events for a customized implementation.

var fileSize = file.files[0].size;
var customXHR = new XMLHttpRequest();
customXHR.upload.addEventListener('progress', function (e) {
    if (e.loaded <= fileSize) {
        var percent = Math.round(e.loaded / fileSize * 100);
        console.log(`Uploaded ${percent}%`);
    } 

    if(e.loaded == e.total){
        console.log("Upload done");
    }
});

imagekit.upload({
    xhr: customXHR,
    file: file.files[0],
    fileName: "abc1.jpg",
    tags: ["tag1"],
    token: 'generated_token',
    signature: 'generated_signature',
    expire: 'generated_expire',
    extensions: [
        {
            name: "aws-auto-tagging",
            minConfidence: 80,
            maxTags: 10
        }
    ]
}).then(result => {
    console.log(result);
}).then(error => {
    console.log(error);
})

Access request-id, other response headers, and HTTP status code

You can access $ResponseMetadata on success or error object to access the HTTP status code and response headers.

// Success
var response = await imagekit.upload({
    file: file.files[0],
    fileName: "abc1.jpg",
    tags: ["tag1"],
    token: 'generated_token',
    signature: 'generated_signature',
    expire: 'generated_expire',
    extensions: [
        {
            name: "aws-auto-tagging",
            minConfidence: 80,
            maxTags: 10
        }
    ]
});
console.log(response.$ResponseMetadata.statusCode); // 200

// { 'content-length': "300", 'content-type': 'application/json', 'x-request-id': 'ee560df4-d44f-455e-a48e-29dfda49aec5'}
console.log(response.$ResponseMetadata.headers);

// Error
try {
    await imagekit.upload({
        file: file.files[0],
        fileName: "abc1.jpg",
        tags: ["tag1"],
        token: 'generated_token',
        signature: 'generated_signature',
        expire: 'generated_expire',
        extensions: [
            {
                name: "aws-auto-tagging",
                minConfidence: 80,
                maxTags: 10
            }
        ]
    });
} catch (ex) {
    console.log(response.$ResponseMetadata.statusCode); // 400

    // {'content-type': 'application/json', 'x-request-id': 'ee560df4-d44f-455e-a48e-29dfda49aec5'}
    console.log(response.$ResponseMetadata.headers);
}