SittenSpynne

So I want to validate something exists on a JS object:

function doSomething(config) {
  // Throw if config.required is not present. 
}

The most obvious way I found to do this at first was to rely on JS's "truthiness" to determine it:

function doSomething(config) {

if (!config.required) {

SittenSpynne

<Window x:Class="MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
    <Window.Background>
        <LinearGradientBrush StartPoint="0,0" EndPoint="0, 1">
            <LinearGradientBrush.GradientStops>
                <GradientStop Color="White" Offset="0.0" />
                <GradientStop Color="Black" Offset="0.4" />
                <GradientStop Color="Black" Offset="0.5" />

SittenSpynne

class FooBase
{
    public FooBase()
    {
        CreateBar();
    }
    
    // "Bar" is usually a pipeline of helper classes that process something Foo is interested in
    // The pipeline varies in each derived type.  Maybe "Initialize" is better.
    protected abstract void CreateBar();

SittenSpynne

    abstract class FooBase
    {
        public string GetMessage()
        {
            return GetMessageCore();
        }

        protected abstract string GetMessageCore();
    }