npm install --save @google-cloud/firestore
npm i --save lodash
Same method could be user for firestore or any Array of data.
Examples shows how to remove duplicates in Array - full firestore implementation - HERE
// clear_dups.js
dupeArray.map((val, indexOut) => {
    const tempObj = val;
    console.log('Original: ', val.title, ' :id: ', val.dupeId);
    dupeArray.map((inVal, indexIn) => {
        if (val.dupeId !== inVal.dupeId) { // IF YOU WANT TO KEEP ORIGINAL DATABASE ITEM
                                            // this will make sure that one item is left and the rest removed
            // change title & user.facebook_post_link to any desired field or add more fields...
            if (val.[YOUR-FIELD-VALUE] === inVal.[YOUR-FIELD-VALUE]) {
                firestore.doc('scraped_posts/' + inVal.dupeId).delete().then(() => {
                    console.log('Found duplicate: ', inVal.[YOUR-FIELD-VALUE], ' :id: ', inVal.dupeId);
                });
            }
        }
    })
})
node deduper-run
Examples shows how to remove single document by ID or title - full firestore implementation - HERE
You can change title field to any other field you may need to delete by.
// delete_single.js
        function deleteById(postID){
            if (postID) {
                firestore.doc('scraped_posts/' + postID).delete().then(() => {
                    console.log('Delete post: ', postID, ' :id: ', postID, ' -DELETED');
                });
            }
        }
        function deleteByTitle(postTitle) {
            if (postTitle) {
                firestore.collection('scraped_posts').where('title', '==', postTitle)
                    .get()
                    .then(querySnapshot => {
                        deleteById( querySnapshot.docs[0].id);
                    })
            }
        }
// delete by id
node run_delete --id 'id of property'
// delete by title
node run_delete --title 'Title of preperty'