@jali-ms/util v0.0.1

Jali Util Package

This package provides JavaScript language level utilities for the Jali microservice platform. jali-ms.io

Utilities include:

• function argument Error types
• argument validator functions
• iteration functions that covers most Array iteration functions and more.
• TypeScript user-defined type guard functions for fundamental JavaScript types.

Getting Started

Install the package:

npm install --save @jali-ms/util

Usage

As a utility package many kinds of functions are provided by a few modules. Major function types are mentioned below. For detailed information see the Jali docs.

Module @jali-ms/util/errors

Provides Error types and function argument verifiers.

Errors

A family of argument errors are available, with the class ArgumentError as the base type in addition to the InvalidStateError, which it thrown when object functions are called when in a state not supported by the operation.

Argument Verifiers

A group of validation errors that throw the appropriate Error when an argument is invalid. Many verifiers provide runtime verification for static type checks provided by TypeScript.

Module @jali-ms/util/iterables

Provides element iteration for any object that implements the iterable pattern.

Example

import Iterables from '@jali-ms/util/iterables';
const sequence = (function*() { yield 1; yield 2; yield 3; })();
const filtered = Iterables.filter(sequence, e => e % 2 === 0);
console.log(Iterables.find(sequence)); // Displays: 2

Module @jali-ms/util/type-guards

Provides type verification functions especially useful for type coercion in TypeScript.

Example

import TypeGuards from '@jali-ms/util/type-guards';
function processException(err: any): void {
  if (TypeGuards.isError(err)) {
    console.log(`An error has occurred: ${err.message}`);
  }
  else {
    console.log(`An error has occurred: ${err.toString()}`);
  }
}

Contribute

This package is part of the monorepo jali-srcs. Please refer to that GitHub repository on how to contribute to the Jali project.