Storage upload trigger 1 - add document to Firestore

trigger 1.java

export const onPic = functions.storage.object().onFinalize(_onPic)
async function _onPic(object: functions.storage.ObjectMetadata): Promise<any> {
    const path = object.name    // "pictures/20180624120000.jpg"
    const id = basename(path, '.jpg')   // "20180624120000"

    try {
        // add a document to Firestore with the details of this pic
        const pic: Pic = {
            id: id,
            date: new Date(),
            imagePath: path,
        }
        await firestore.collection('pics').doc(id).set(pic)
    // ... skip ...
    }
}