Dynamodeve

An easier method to use AWS DynamoDB. It handles index generation but giving you more control to declare indexes and query patterns.

Install

npm install dynamodeve

Setup

1. Declare your table configuration

// db_config.ts

const TABLE_NAME = 'main';

export const PRIMARY_INDEX_CONFIG = {
    tableName: TABLE_NAME,
    indexName: null,
    partitionKey: 'PK',
    sortKey: 'SK',
} as const;

export const GSI1_CONFIG = {
    tableName: TABLE_NAME,
    indexName: 'GSI1',
    partitionKey: 'GSI1PK',
    sortKey: 'GSI1SK',
} as const;

export const GSI2_CONFIG = {
    tableName: TABLE_NAME,
    indexName: 'GSI2',
    partitionKey: 'GSI2PK',
    sortKey: 'GSI2SK',
} as const;

2. Create a model using the configuration

// user.ts

type User = {
    givenName: string;
    lastName: string;
    email: string;
    nationalId: string;
}

Declare your model entity name

const ENTITY_NAME = 'User';

Declare your model index configuration, for this step you can use curly braces as template fields for the lib to generate your indexes

// user.ts

const INDEX_FIELDS_MAP: IndexFieldsMap = {
    [PRIMARY_INDEX_CONFIG.partitionKey]: [ENTITY_NAME, '{id}'],
    [PRIMARY_INDEX_CONFIG.sortKey]: [ENTITY_NAME],
    [GSI1_CONFIG.partitionKey]: [ENTITY_NAME],
    [GSI1_CONFIG.sortKey]: [ENTITY_NAME, '{email}'],
    [GSI2_CONFIG.partitionKey]: [ENTITY_NAME],
    [GSI2_CONFIG.sortKey]: [ENTITY_NAME, '{nationalId}'],
};

After index generation the above will generate indexes like

PK: User#937c1e16-cb48-454d-825b-7398ab990d91
SK: User

GSI1PK: User
GSI1SK: User#[email protected]

GSI2PK: User
GSI2SK: User#13812718

The next step is to declare your wrapper model

// user.ts

export class Handler extends DbModel<Entity> {
    constructor(pkPrefix: string) {
        super(pkPrefix, ENTITY_NAME, PRIMARY_INDEX_CONFIG, INDEX_FIELDS_MAP);
    }

    // Primary Access patterns

    public async findOneById(id: string): Promise<Entity | null> {
        return this.queryOne({ id }, PRIMARY_INDEX_CONFIG, { skMatch: 'exact' });
    }

    // GSI1 Access patterns

    public async find(config: PaginationConfig = {}): Promise<PaginatedDbResult<Entity[]>> {
        return await this.query({}, GSI1_CONFIG, { ...config, skMatch: 'begins_with' });
    }

    public async findOneByEmail(email: string): Promise<Entity | null> {
        return this.queryOne({ email }, GSI1_CONFIG, { skMatch: 'exact' });
    }

    // GSI2 Access patterns

    public async findOneByNationalId(nationalId: string): Promise<Entity | null> {
        return this.queryOne({ nationalId }, GSI2_CONFIG, { skMatch: 'exact' });
    }

    // CRUD operations

    public async createOne(input: WithoutDefaults<Entity>): Promise<Entity> {
        const { id } = this.trxInsertOne(input);

        this.trxInsertUniqueConstraint([input.email]);

        if (input.nationalId) {
            this.trxInsertUniqueConstraint([input.nationalId]);
        }

        await this.trxExecute();

        const createdResource = await this.findOneById(id);
        if (createdResource === null) {
            throw new Error('Failed to find resource after create');
        }

        return createdResource;
    }

    public async updateOne(id: string, input: Partial<WithoutDefaults<Entity>>, filter: Partial<Entity> = {}): Promise<Entity | null> {
        const resource = await this.findOneById(id);
        if (resource === null) return null;

        this.trxUpdateOne(input, resource, filter);

        if (input.email && input.email !== resource.email) {
            this.trxRemoveUniqueConstraint([resource.email]);
            this.trxInsertUniqueConstraint([input.email]);
        }

        if (input.nationalId && input.nationalId !== resource.nationalId) {
            if (resource.nationalId) {
                this.trxRemoveUniqueConstraint([resource.nationalId]);
            }
            this.trxInsertUniqueConstraint([input.nationalId]);
        }

        await this.trxExecute();

        return this.findOneById(id);
    }

    public async deleteOne(id: string, filter: Partial<Entity> = {}): Promise<Entity | null> {
        const resource = await this.findOneById(id);
        if (resource === null) return null;

        this.trxDeleteOne(resource, filter);

        this.trxRemoveUniqueConstraint([resource.email]);

        if (resource.nationalId !== undefined) {
            this.trxRemoveUniqueConstraint([resource.nationalId]);
        }

        await this.trxExecute();

        return resource;
    }
}