Purpose

Some time our API data requirement is less strict, we do not want to reject the whole data just because:

1. some information is incorrect
2. extra information

At the same time we don't want to save them into database, we just want to save whatever that is correct.

This is where filtering come in handy.

Installation

npm i firesword zod

Note

1. Remove all incorrect enumerable keys(members where key or value type is incorrect), which mean it works for array too.
2. Filters recursively, nothing can escape, it is a black hole.
3. Does not throw on missing members, the job is to filter, not validating. In case you need to throw(validate), see point 4.
4. To validate, simply call yourSchema.parse(data) or yourSchema.safeParse(data) depend on your use case. Keep in mind all members is required by default, you can set all members or certain members to partial, please read the Zod documentation for more parsing options.
5. Filters do not care zod partial option and if you want to validate(you should), it is important to validate first before you filter, not the other way around.
6. Both Firestore and RTDB filters support native Zod types: z.literal, z.string, z.number, z.null, z.boolean, z.array, z.union, z.object.
7. This library is structure in a way that it is possible to support other database(open an issue for other databases support).

Limitations For Both RTDB and Firestore Filters

1. Do not union object type with any other type: z.union([z.object({}), z.someOtherType])
2. Do not union array type with any other type: z.union([z.array(...), z.someOtherType])
3. Top level data type must be an object type.

Firestore Quick Start

1. zTimestamp, zDocumentReference and zGeoPoint, zArrayUnionAndRemove, zDelete, zIncrement and zServerTimestamp are custom Firestore Zod types.
2. Support native Zod Type: z.date.
3. The filtered data is deep clone of original data, will not clone Firestore Timestamp, DocumentReference, GeoPoint and all field values(ServerTimestamp, ArrayRemove, ArrayUnion, Increment, Delete).

Web

import {
	filter,
	zTimestamp,
	zDocumentReference,
	zGeoPoint,
	zArrayUnionAndRemove,
	zDelete,
	zIncrement,
} from 'firesword/firestore-web'
import { z } from 'zod'
import {
	Timestamp,
	getFirestore,
	doc,
	arrayRemove,
	deleteField,
	increment,
} from 'firebase/firestore'
import { initializeApp } from 'firebase/app'

initializeApp({ projectId: 'any' })

// {
// 	a: string
// 	b: 1 | 2 | 3
// 	c: {
// 		d: Timestamp
// 		e: DocumentReference
// 		f: GeoPoint
// 	}
// 	d: number[]
// 	e: { i: boolean; j: 'a' | 'b' | 'c' }[]
//  f: (number|boolean)[]
//  g: string[]
//  h: number
//  i: number
//  j: Date
// }
const schema = z.object({
	a: z.string(),
	b: z.union([z.literal(1), z.literal(2), z.literal(3)]),
	c: z.object({ d: zTimestamp(), e: zDocumentReference(), f: zGeoPoint() }),
	d: z.array(z.number()),
	e: z.array(
		z.object({
			i: z.boolean(),
			j: z.union([z.literal('a'), z.literal('b'), z.literal('c')]),
		})
	),
	f: z.array(z.union([z.boolean(), z.number()])),
	g: z.union([z.array(z.string()), zArrayUnionAndRemove(z.string())]),
	h: z.union([zDelete(), z.number()]),
	i: z.union([zIncrement(), z.number()]),
	j: z.date(),
})

export const filteredData = filter({
	schema,
	data: {
		// 'a' is missing
		z: 'unknown member',
		b: 1,
		c: {
			d: new Timestamp(0, 0),
			e: doc(getFirestore(), 'a/b'),
			// f is missing
			z: 'unknown member',
		},
		d: [100, 200, 300],
		e: [
			{
				i: true,
				// j is missing
			},
			{
				// i is missing
				j: 'a',
				z: 'unknown member',
			},
		],
		f: arrayRemove('abc'),
		g: deleteField(),
		h: increment(1),
		i: new Date(0),
	},
})

// console.log(filteredData)
// {
// 	b: 1,
// 	c: {
// 		d: new Timestamp(0, 0),
// 		e: doc(getFirestore(), 'a/b'),
// 	},
// 	d: [100, 200, 300],
// 	e: [{ i: true }, { j: 'a' }],
//  f: arrayRemove('abc'),
//  g: deleteField(),
//  h: increment(1),
//  i: new Date(0),
// }

Admin

This is how you import the same thing in admin, the rest are similar to web.

import {
	filter,
	zTimestamp,
	zDocumentReference,
	zGeoPoint,
	zArrayUnionAndRemove,
	zDelete,
	zIncrement,
} from 'firesword/firestore-admin'

RTDB Quick Start

1. zServerTimestamp and zIncrement are custom RTDB Zod types.
2. Use zServerTimestamp for serverTimestamp and zIncrement for increment.
3. RTDB's zServerTimestamp and zIncrement are not the same as Firestore's zServerTimestamp and zIncrement.
4. RTDB doesn't always return array type. <-- this does not affect how you should use this library but something you should be aware of.
5. One api for both admin and web.

import { filter, zServerTimestamp, zIncrement } from 'firesword/database'
import { z } from 'zod'
import { serverTimestamp, increment } from 'firebase/database'
// {
// 	a: string
// 	b: number
// 	g: serverTimestamp[]
// 	h: { i: boolean; j: 'a' | 'b' | 'c' }[]
// }
const schema = z.object({
	a: z.string(),
	b: z.union([z.number(), zIncrement()]),
	g: z.array(zServerTimestamp()),
	h: z.array(
		z.object({
			i: z.boolean(),
			j: z.union([z.literal('a'), z.literal('b'), z.literal('c')]),
		})
	),
})

export const filteredData = filter({
	schema,
	data: {
		// missing 'a'
		z: 'unknown member',
		b: increment(1),
		g: [serverTimestamp(), serverTimestamp(), serverTimestamp()],
		h: [
			{
				i: true,
				// missing j
			},
			{
				// missing i
				j: 'a',
				z: 'unknown member',
			},
		],
	},
})

// console.log(filteredData)
// {
// 	b: increment(1),
// 	g: [ServerTimestamp, ServerTimestamp, ServerTimestamp],
// 	h: [{ i: true }, { j: 'a' }],
// }

Dealing With Incorrect Data Type

This section use Firestore filter as example but the same logic is applied to RTDB filter.

import { filter, zArrayUnionAndRemove } from 'firesword/firestore-web'
import { number, z } from 'zod'
import { arrayUnion } from 'firebase/firestore'
// {
// 	a: string
// 	b: 1 | 2 | 3
// 	g: { x: number, y: null }
// 	h: boolean[]
//  i: zArrayUnionAndRemove(string)
// }
const schema = z.object({
	a: z.string(),
	b: z.union([z.literal(1), z.literal(2), z.literal(3)]),
	g: z.object({ x: z.number(), y: z.null() }),
	h: z.array(z.boolean()),
	i: zArrayUnionAndRemove(z.string()),
	j: z.array(
		z.object({ x: z.number(), y: z.object({ a: z.null(), b: z.number() }) })
	),
})

export const filteredData = filter({
	schema,
	data: {
		a: true, // expect string
		b: {}, // expect 1 | 2 | 3
		g: 1, // expect { x:number, y:null }
		h: null, // expect boolean[]
		i: arrayUnion(1), // expect arrayUnion(string)
		j: [{ x: 'abc', y: { a: null, b: 'abc' } }], // expect number for 'x' and 'b'
	},
})
// console.log(filteredData) // { j:[{y: { a:null }}] }

export const filteredData2 = filter({
	schema,
	data: {
		g: { a: {}, b: true, c: 'abc' }, // expect { x:number, y:null }
		h: [1, true, 3], // expect boolean[], only the 2nd element is correct
	},
})
// console.log(filteredData2) // { g: {}, h: [null, true, null] }

Special Types Type Casting

You need to type cast Firestore zTimestamp, zDocumentReference and zGeoPoint.

import {
	filter,
	zTimestamp,
	zDocumentReference,
	zGeoPoint,
} from 'firesword/firestore-web'
import { z } from 'zod'
import {
	Timestamp,
	doc,
	GeoPoint,
	DocumentReference,
	getFirestore,
} from 'firebase/firestore'
import { initializeApp } from 'firebase/app'

initializeApp({ projectId: 'any' })

// {
// 	d: Timestamp
// 	e: DocumentReference
// 	f: GeoPoint
// }
const schema = z.object({
	d: zTimestamp(),
	e: zDocumentReference(),
	f: zGeoPoint(),
})

export const filteredData = filter({
	schema,
	data: {
		d: new Timestamp(0, 0),
		e: doc(getFirestore(), 'a/b'),
		f: new GeoPoint(0, 0),
	},
}) as unknown as {
	d: Timestamp
	e: DocumentReference
	f: GeoPoint
}

In Case of Compiler Ignoring Package.json Exports

If you see error like Cannot find module 'firesword/firestore' or Cannot find module 'firesword/database', it means your compiler ignore package.json exports field.

Solution for Jest: jest-node-exports-resolver.

I am not aware of solution for other cases(eg webpack), please open issue if you are having similar issue.

Trivial

1. The name FireSword is a reference to Piandao of Avatar.
2. This library is the successor of FireLaw.

Related Projects

1. FirelordJS - Typescript wrapper for Firestore Web
2. Firelord - Typescript wrapper for Firestore admin
3. FireCall - Helper Function to write easier and safer Firebase onCall function.
4. FireSageJS - Typescript wrapper for Realtime Database Web