Collection of Reusable TypeScript Classes, Functions, and Types for Common Use Cases

How To use

Installation

only available on the GitHub registry

npm install @santiagoziel/service-utils

env_configuration class

The env_config class allows you to retrieve values from environment variables and handle cases where the environment variables are not set or have the wrong data type. It provides several methods for retrieving values from environment variables:

Example

import {env_config} from "@santiagoziel/service-utils"
const config = new env_config()

//please dont log your secrets this is just an example
console.log(config.stringOrError("SECRET_KEY"));

Several options to retrieve env variables are available. Check @santiagoziel/service-utils/dist/config.d.ts for more info

AppError class

AppError is a custom error class that extends the built-in Error class in Typescript. It adds a code property to the error object, which can be useful in identifying specific types of errors for HTTP.

Example

async helow(credentials: gateWayModels.SuperUserCredentials){
    try{
      const authResult = await authorizeUser(credentials.username, credentials.password);
      if (authResult.status == 'failed') throw new AppError(authResult.reason , 401);
      return {status: "authorized"}}
    catch (error: any) {
      return { status: 'failed', reason: error.message, code: error.code };
      }
    }

Resolution type

The Resolution type represents the result of an operation that can either succeed or fail. It has two possible states:

• succeded: The operation was successful and the result is available in the value field, which is of the first generic type A provided.
• failed: The operation failed and the reason for the failure is available in the reason field, which is of the second generic type B provided with a default of string.

Example

type Error = {message: string, code: number};

function divide(a: number, b: number): Resolution<number, Error> {
  if (b === 0) {
    return { status: "failed", reason: { message: "Cannot divide by zero.", code: 400 } };
  }
  return { status: "succeded", value: a / b };
}

const result = divide(10, 2);

if (result.status === "succeded") {
  console.log(result.value); // 5
} else {
  console.log(result.reason.message); // "Cannot divide by zero."
  console.log(result.reason.code); // 400
}

preload function

The preload function creates a new function that calls a given callback with pre-defined arguments. This can be useful for creating functions that are pre-loaded with certain arguments and can be called later, without having to pass the arguments every time.

Example

import {preload} from "@santiagoziel/service-utils"

const logString = (a: string) => console.log(a);

const loaded = preload(logString, "Hi!");

loaded(); // logs "Hi!"

sendPushNotification function

The sendPushNotification function is a utility function that sends a push notification to a specified device using the Pushover API. The function takes in the necessary parameters such as the user key, app key, message, and device, and sends the notification with an optional priority level and expiration time.

Example

sendPushNotification("Your User Key", "Your app Key", "Hello World!", "phone123");