noldova.context.exceptions

The exceptions CONTEXT libraries throw: an abstract Exception base that names itself after its concrete class, argument exceptions with guards that check a value and narrow its type in one call, and an index exception.

Install

npm install @noldova/context.exceptions

Use

import { ArgumentException, ArgumentNullException, Exception, ExceptionOptions } from "@noldova/context.exceptions";

class InputException extends Exception {
  public constructor(message: string, options?: ExceptionOptions) {
    super(message, options);
  }
}

function readName(values: Map<string, string>): string {
  const name = values.get("name");
  ArgumentException.throwIfNullOrWhitespace(name, "name");
  return name; // Narrowed to string by the guard.
}

readName(new Map([["name", "Fixture"]])); // "Fixture"
new ArgumentNullException("input").message; // "Value cannot be null or undefined. (Parameter 'input')"
new InputException("Cannot read input.", new ExceptionOptions(new Error("Bad encoding."))).name; // "InputException"

ArgumentException, ArgumentNullException and ArgumentOutOfRangeException keep the parameter name as a field, and ArgumentOutOfRangeException also keeps the rejected value. IndexOutOfRangeException carries a message and, where given, a cause. The declaration file api/index.d.ts documents every member with its contract and examples.

License

MIT; see LICENSE.