CheckVerify

A simple library for checking preconditions on functions. Heavily inspired by Guava's Precondition.

Methods starting with verify throw on failure, while methods starting with is return boolean.

Sample usages

import { Check } from "@awkewainze/checkverify";

function doThing(param1: number, param2: string): void {
    Check.verifyPositive(param1); // If `param1 <= 0` then throws generic error.
    Check.verifyNotNullUndefinedOrEmpty(param2); // If param is `null`, `undefined`, or an empty string then throws generic error.
    Check.verify(param1 < 100);

    // Do things...
}

import { Check } from "@awkewainze/checkverify";

function doThing(param1: number): void {
    if (!Check.isPositive(param1)) {
        param1 = 1;
    }

    // Do things...
}

For more examples, check the check.test.ts file!

Custom errors

To throw your own error or message, just pass as the second parameter.

import { Check } from "@awkewainze/checkverify";

function doThing(param1: number, param2: string): void {
    Check.verifyPositive(param1, "param1 was not positive"); // Throws error with message provided.
    Check.verifyNotNullUndefinedOrEmpty(param2, new Error("param2 was null or empty"));
    Check.verify(param1 < 100, "param1 must be less than 100");

    // Do things...
}

Notes

I will slowly add more useful checks over time as I need them, I just hate having to repeat code in multiple projects, and the verify methods make error handling super easy.