react-native-template-mrf/project/src/manipulate_image.js

const sharp = require('sharp')
const fs = require('fs')
const { promisify } = require('util')

let config = {}

const resizeFile = async ({ file, path, width, height, round = false }) => {
    const localFile = `./asset/${config.originalFile}`

    const targetFile = file || config.file
    if (!targetFile) {
        throw { message: 'No input file' }
    }

    const exists = promisify(fs.exists)
    if (!(await exists(localFile))) {
        throw { message: 'File not found' }
    }
    
    const destPath = [config.destinationPath, path].filter(e => !!e).join('/')
    
    if (!(await exists(destPath))) {
        await promisify(fs.mkdir)(destPath)
    }
    
    const outputFile = `${destPath}/${targetFile}.${config.extension}`
    const builder = await sharp(localFile).resize({ width, height })
    
    if (round) {
        const hh = height || width
        const roundedCorners = Buffer.from(`<svg><rect x="0" y="0" width="${width}" height="${hh}" rx="${width / 2}" ry="${hh / 2}"/></svg>`)
        builder.composite([
            {
                input: roundedCorners,
                blend: 'dest-in',
            },
        ])
    }
    
    console.log(`Converting ${localFile} to ${outputFile}...`)
    return builder.toFile(outputFile)
}

module.exports = {
    setConfig: ({ originalFile, destinationPath, file, extension = 'png' }) => {
        config = { originalFile, destinationPath, file, extension }
    },
    resize: resizeFile,
    getStats: async file => {
        const stats = await sharp(file).metadata()
        return { ...stats, ratio: stats.width / stats.height }
    }
}