DDB key value store

DDBKeyValueStore.ts

import { DocumentClient } from "aws-sdk/clients/dynamodb";

export interface AsyncKeyValueStore<K> {
  set<V>(key: K, value: V): Promise<void>;
  get<V>(key: K): Promise<V>;
  remove(key: K): Promise<void>;
}

export class DynamoDBKeyValueStore<K> implements AsyncKeyValueStore<K> {
  docClient: DocumentClient;
  tableName: string;

  constructor(docClient: DocumentClient, tableName: string) {
    this.docClient = docClient;
    this.tableName = tableName;
  }

  remove = (key: K): Promise<void> => {
    return new Promise((resolve, reject) => {
      this.docClient.delete(
        {
          TableName: this.tableName,
          Key: {
            ItemKey: key
          }
        },
        (err, _data) => {
          if (err) return reject(err);
          resolve();
        }
      );
    });
  };

  set = <V>(key: K, value: V): Promise<void> => {
    return new Promise((resolve, reject) => {
      this.docClient.put(
        {
          TableName: this.tableName,
          Item: {
            ItemKey: key,
            ItemValue: JSON.stringify(value)
          }
        },
        (err, _data) => {
          if (err) return reject(err);
          resolve();
        }
      );
    });
  };

  get = <V>(key: K): Promise<V> => {
    return new Promise((resolve, reject) => {
      this.docClient.get(
        {
          TableName: this.tableName,
          Key: {
            ItemKey: key
          }
        },
        (err, data) => {
          if (err || !data.Item) return reject(err);
          resolve(JSON.parse(data.Item["ItemKey"]));
        }
      );
    });
  };
}