Create data source for tdsvc

datasource.ts

import { readFileSync, writeFileSync } from "fs";
import { item, user } from "./models";

const ITEMS_SOURCE = "data/items.json";
const USERS_SOURCE = "data/users.json";

const load_items = (): Array<item> => {
  const data = readFileSync(ITEMS_SOURCE, "utf-8");
  if (!data) {
    return [];
  }
  return JSON.parse(data);
};

const load_users = (): Array<user> => {
  const data = readFileSync(USERS_SOURCE, "utf-8");
  if (!data) {
    return [];
  }
  return JSON.parse(data);
};

const write_items = (items: Array<item>): void => {
  const data = JSON.stringify(items);
  writeFileSync(ITEMS_SOURCE, data);
};

const write_users = (users: Array<user>): void => {
  const data = JSON.stringify(users);
  writeFileSync(USERS_SOURCE, data);
};

export const get_item = (id: number): item => {
  const items = load_items();
  return items.find((i) => i.id == id);
};

export const add_item = (item: item): string => {
  const items = load_items();
  const new_items = items.concat(item);
  try {
    write_items(new_items);
    return "Successfullly added item";
  } catch (error) {
    return `Cannot add due to ${error}`;
  }
};

export const get_user = (id: number): user => {
  const users = load_users();
  return users.find((i) => i.id == id);
};

export const add_users = (user: user): string => {
  const users = load_users();
  const new_users = users.concat(user);
  try {
    write_users(new_users);
    return "Successfullly added user";
  } catch (error) {
    return `Cannot add due to ${error}`;
  }
};

items.json

[
    {
        "id": 1,
        "task": "Prepare Coffee",
        "priority": 1,
        "date": "2021-05-01"
    },
    {
        "id": 2,
        "task": "Boil Eggs",
        "priority": 2,
        "date": "2021-05-01"
    },
    {
        "id": 3,
        "task": "Buy Milk",
        "priority": 3,
        "date": "2021-05-01"        
    }
]

models.ts

export interface item {
  id: number;
  task: string;
  priority: number;
  date: Date;
}

export interface user {
  id: number;
  first_name: string;
  last_name: string;
}

users.json

[
    {
        "id": 1,
        "first_name": "John",
        "last_name": "Doe"
    },
    {
        "id": 2,
        "first_name": "Brad",
        "last_name": "Gabson"
    },
    {
        "id": 3,
        "first_name": "Allen",
        "last_name": "Ray"
    }
]