firebase_upload_base64.js

exports.uploadExpoImage = functions.https.onCall(
	async ({ data_url, path }, context) => {
		try {
			let base64EncodedImageString = `${data_url}`.replace(
				'data:image/png;base64,',
				''
			)
			let mimeType = 'image/png'
			let imageBuffer = new Buffer(base64EncodedImageString, 'base64')
			let bucket = admin.storage().bucket()
			let file = bucket.file(path)
			await file.save(imageBuffer, {
				metadata: { contentType: mimeType }
			})
			let url =
				'https://firebasestorage.googleapis.com/v0/b/appid.appspot.com/o/'
			url += path.replace(/\//g, '%2F')
			url += '?alt=media'
			return url
		} catch (e) {
			return null
		}
	}
)