npm package: @magnify-cash/nft-lists
Description: 📫 The NFT Lists specification
Author: Magnify Cash
Latest version: 0.0.1

# @magnify-cash/nft-lists

This package includes a JSON schema for NFT lists, and TypeScript utilities for working with NFT lists.

The JSON schema represents the technical specification for an NFT list which can be used in a dApp interface, such as the Magnify Cash Interface.

This work stands on the shoulders of Uniswap Labs and their work for an ERC20 token specification in  [Token Lists](https://github.com/Uniswap/token-lists/)


## What are nft lists?
Magnify Cash NFT Lists is is a specification for lists of NFT metadata (e.g. address, decimals, ...) that can be used by any dApp interfaces that needs one or more lists of NFTs.

Specifically an instance of a NFT list is a [JSON](https://www.json.org/json-en.html) blob that contains a list of
[ERC721](https://github.com/ethereum/eips/issues/721) or [ERC1155](https://github.com/ethereum/eips/issues/1155) NFT metadata for use in dApp user interfaces.

NFT list JSON must validate against the [JSON schema](https://json-schema.org/) in order to be used in the Magnify Cash Interface. NFTs on NFT lists, and NFT lists themselves, are tagged so that users can easily find NFTs.

## JSON Schema $id

The JSON schema ID is [http://magnify-cash.io/tokenlist.schema.json](http://magnify-cash.io/tokenlist.schema.json)

## Validating NFT lists

This package does not include code for NFT list validation. You can easily do this by including a library such as
[ajv](https://ajv.js.org/) to perform the validation against the JSON schema. The schema is exported from the package
for ease of use.

```typescript

import { schema } from '@magnify-cash/nft-lists'
import Ajv from 'ajv'
import addFormats from 'ajv-formats'
import fetch from 'node-fetch'

const ARBITRUM_LIST = "TODO"

async function validate() {
  const ajv = new Ajv({ allErrors: true, verbose: true })
  addFormats(ajv)
  const validator = ajv.compile(schema);
  const response = await fetch(ARBITRUM_LIST)
  const data = await response.json()
  const valid = validator(data)
  if (valid) {
  return valid
  }
  if (validator.errors) {
  throw validator.errors.map(error => {
    delete error.data
    return error
  })
  }
}

validate()
  .then(console.log("Valid List."))
  .catch(console.error)

```

## Authoring NFT lists

### Manual

The best way to manually author NFT lists is to use an editor that supports JSON schema validation. Most popular
code editors do, such as [IntelliJ](https://www.jetbrains.com/help/idea/json.html#ws_json_schema_add_custom) or
[VSCode](https://code.visualstudio.com/docs/languages/json#_json-schemas-and-settings). Other editors
can be found [here](https://json-schema.org/implementations.html#editors).

The schema is registered in the [SchemaStore](https://github.com/SchemaStore/schemastore), and any file that matches
the pattern `*.nftlist.json` should
[automatically utilize](https://www.jetbrains.com/help/idea/json.html#ws_json_using_schemas)
the JSON schema for the [supported text editors](https://www.schemastore.org/json/#editors).

In order for your NFT list to be able to be used, it must pass all JSON schema validation.

### Automated

If you want to automate NFT listing, e.g. by pulling from a smart contract, or other sources, you can use this
npm package to take advantage of the JSON schema for validation and the TypeScript types.
Otherwise, you are simply working with JSON. All the usual tools apply, e.g.:

```typescript
import { NFTList, schema } from '@magnify-cash/nft-lists'

// generate your nft list however you like.
const myList: NFTList = generateMyNFTList();

// use a tool like `ajv` to validate your generated nft list
validateMyNFTList(myList, schema);

// print the resulting JSON to stdout
process.stdout.write(JSON.stringify(myList));
```

## Semantic versioning

Lists include a `version` field, which follows [semantic versioning](https://semver.org/).

List versions must follow the rules:

- Increment major version when NFTs are removed
- Increment minor version when NFTs are added
- Increment patch version when NFTs already on the list have minor details changed (name, symbol, logo URL, decimals)

Changing a NFT address or chain ID is considered both a remove and an add, and should be a major version update.

Note that list versioning is used to improve the user experience, but not for security, i.e. list versions are not meant
to provide protection against malicious updates to a NFT list; i.e. the list semver is used as a lossy compression
of the diff of list updates. List updates may still be diffed in the client dApp.

## Deploying your list

Once you have authored the list, you can make it available at any URI. Prefer pinning your list to IPFS
(e.g. via [pinata.cloud](https://pinata.cloud)) and referencing the list by an ENS name that resolves to the
[contenthash](https://eips.ethereum.org/EIPS/eip-1577).

If hosted on HTTPS, make sure the endpoint is configured to send an access-control-allow-origin header to avoid CORS errors.

### Linking an ENS name to the list

An ENS name can be assigned to an IPFS hash via the [contenthash](https://eips.ethereum.org/EIPS/eip-1577) text record.
This is the preferred way of referencing your list.

## Examples
You can find a simple example of a nft list in test/schema/example.nftlist.json.

A snapshot of the Magnify Cash default list encoded as a nft list is found in test/schema/bigexample.nftlist.json.