Cropping and resizing images in React

npm install react-easy-crop --save

yarn add react-easy-crop

// ImageCropper.js

import React, { useState } from 'react'
import Cropper from 'react-easy-crop'
import { getCroppedImg } from './cropImage'

const ImageCropper = ({ getBlob, inputImg }) => {
    const [crop, setCrop] = useState({ x: 0, y: 0 })
    const [zoom, setZoom] = useState(1)

    /* onCropComplete() will occur each time the user modifies the cropped area, 
    which isn't ideal. A better implementation would be getting the blob 
    only when the user hits the submit button, but this works for now  */
    const onCropComplete = async (_, croppedAreaPixels) => {
        const croppedImage = await getCroppedImg(
            inputImg,
            croppedAreaPixels
        )
        getBlob(croppedImage)
    }

    return (
        /* need to have a parent with `position: relative` 
    to prevent cropper taking up whole page */
        <div className='cropper'> 
            <Cropper
                image={inputImg}
                crop={crop}
                zoom={zoom}
                aspect={1}
                onCropChange={setCrop}
                onCropComplete={onCropComplete}
                onZoomChange={setZoom}
            />
        </div>
    )
}

export default ImageCropper

// ImageUpload.js

import React, { useState } from 'react'
import * as firebase from 'firebase/app'
import ImageCropper from './ImageCropper'

const ImageUpload = () => {
    const [blob, setBlob] = useState(null)
    const [inputImg, setInputImg] = useState('')

    const getBlob = (blob) => {
        // pass blob up from the ImageCropper component
        setBlob(blob)
    }

    const onInputChange = (e) => {
        // convert image file to base64 string
        const file = e.target.files[0]
        const reader = new FileReader()

        reader.addEventListener('load', () => {
            setInputImg(reader.result)
        }, false)

        if (file) {
            reader.readAsDataURL(file)
        }
    }

    const handleSubmitImage = (e) => {
    // upload blob to firebase 'images' folder with filename 'image'
        e.preventDefault()
        firebase
            .storage()
            .ref('images')
            .child('image')
            .put(blob, { contentType: blob.type })
            .then(() => {
                // redirect user 
            })
    }


    return (
        <form onSubmit={handleSubmitImage}>
            <input
                type='file'
                accept='image/*'
                onChange={onInputChange}
            />
            {
                inputImg && (
                    <ImageCropper
                        getBlob={getBlob}
                        inputImg={inputImg}
                    />
                )
            }
            <button type='submit'>Submit</button>
        </form>
    )
}

export default ImageUpload

// cropImage.js

// create the image with a src of the base64 string
const createImage = (url) =>
    new Promise((resolve, reject) => {
        const image = new Image()
        image.addEventListener('load', () => resolve(image))
        image.addEventListener('error', error => reject(error))
        image.setAttribute('crossOrigin', 'anonymous')
        image.src = url
    })

export const getCroppedImg = async (imageSrc, crop) => {
    const image = await createImage(imageSrc)
    const canvas = document.createElement('canvas')
    const ctx = canvas.getContext('2d')

    /* setting canvas width & height allows us to 
    resize from the original image resolution */
    canvas.width = 250
    canvas.height = 250

    ctx.drawImage(
        image,
        crop.x,
        crop.y,
        crop.width,
        crop.height,
        0,
        0,
        canvas.width,
        canvas.height
    )

    return new Promise((resolve) => {
        canvas.toBlob((blob) => {
            resolve(blob)
        }, 'image/jpeg')
    })
}