@michaelcoxon/ensure

# ensure-js A port of EnsureFramework for JavaScript/TypeScript.

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Argument assertion with ease

Ensure is designed to take the pain out of null checking and making sure (ensuring) your methods are being used the way they were intended and throwing exceptions when unsupported values are passed to them.

You can make sure values are in a specific range or simply make sure that an argument is not null.

It was designed to be readable and fluent based, meaning you can chain ensurables together and the first one that fails will result in the exception.

Installation

It's in NPM man...

npm i @michaelcoxon/ensure --save

Usage

NOTE: Check the tests for full documentation. I am getting to filling out this readme file as I can. The tests have full coverage though.

It's designed to be a one-liner to assert that your arguments are within the bounds of the method. So using it is as simple as...

Ensure.arg(         // Step 1: open up the fluent interface
    myArgument,     // Step 2: pass in your argument
    "myArgument"    // Step 3: tell it the name of your argument
    )               // Step 4: ???
    .isNotNull();   // Step 5: Make your assertions/profit!!

Your assertions can be chained and will execute in the order defined for example

Ensure.arg(str, "str")
    .isNotNull()
    .isOneOf("str", "foo", "bar");

Strings

Ensure a string is not null

function testMethod(str: string | null)
{
    Ensure.arg(str, "str").isNotNull();
}