From 28f0271f25b4f6168a1d6cf8fa4af35d356e5bbb Mon Sep 17 00:00:00 2001
From: Nathan Kluth <nlkluth@gmail.com>
Date: Thu, 9 Nov 2023 12:42:51 -0700
Subject: [PATCH] refactor: polymorphic component (#211)

* refactor: polymorphic component

* cleanup
---
 packages/nextjs/components/Card.tsx           |  6 +-
 .../shared-ui/components/Button/Button.tsx    | 55 ++++++------------
 packages/shared-ui/components/Card/Card.tsx   | 27 +++++----
 .../shared-ui/uitls/polymorphicComponent.ts   | 57 +++++++++++++++++++
 4 files changed, 91 insertions(+), 54 deletions(-)
 create mode 100644 packages/shared-ui/uitls/polymorphicComponent.ts

diff --git a/packages/nextjs/components/Card.tsx b/packages/nextjs/components/Card.tsx
index e8236b4a..52161acf 100644
--- a/packages/nextjs/components/Card.tsx
+++ b/packages/nextjs/components/Card.tsx
@@ -29,11 +29,11 @@ export const Card = ({
     <BaseCard
       title={title}
       subTitle={subTitle}
-      to={to}
       price={price}
-      className={className}
       imageContainerClass={containerClassName}
-      Link={Link}
+      as={Link}
+      href={to}
+      className={className}
     >
       <Image layout="fill" src={imageProps.src} alt={imageProps.alt} objectFit="cover" objectPosition="center" />
     </BaseCard>
diff --git a/packages/shared-ui/components/Button/Button.tsx b/packages/shared-ui/components/Button/Button.tsx
index c818c13a..fb80ac4f 100644
--- a/packages/shared-ui/components/Button/Button.tsx
+++ b/packages/shared-ui/components/Button/Button.tsx
@@ -1,31 +1,22 @@
-import type { AnchorHTMLAttributes, ButtonHTMLAttributes, ForwardedRef } from "react";
-import * as React from "react";
 import classNames from "classnames";
+import { forwardRef } from "react";
+import { PolymorphicComponentPropsWithRef, PolymorphicRef } from "../../uitls/polymorphicComponent";
 
-interface BaseProps {
+export interface ButtonProps {
+  children?: React.ReactNode;
   variant: "primary" | "secondary" | "tertiary" | "text";
-  disabled?: boolean;
-  children: React.ReactNode;
   leftIcon?: React.ReactNode;
   rightIcon?: React.ReactNode;
 }
 
-type ButtonAsButton = BaseProps &
-  Omit<ButtonHTMLAttributes<HTMLButtonElement>, keyof BaseProps> & {
-    as?: "button";
-  };
+type CombinedProps<T extends React.ElementType> = PolymorphicComponentPropsWithRef<T, ButtonProps>;
+type ButtonComponent = <C extends React.ElementType = "button">(props: CombinedProps<C>) => React.ReactElement | null;
 
-type ButtonAsLink = BaseProps &
-  Omit<AnchorHTMLAttributes<HTMLAnchorElement>, keyof BaseProps> & {
-    as: "a";
-  };
-
-type ButtonProps = ButtonAsButton | ButtonAsLink;
-
-function ButtonComponent(
-  { as = "button", variant, disabled, className, leftIcon, rightIcon, ...props }: ButtonProps,
-  ref: ForwardedRef<HTMLButtonElement | HTMLAnchorElement>
-) {
+const ButtonComponent = <T extends React.ElementType = "button">(
+  { as, variant, className, children, leftIcon, rightIcon, ...componentProps }: CombinedProps<T>,
+  ref: PolymorphicRef<T>
+) => {
+  const Component = as || "button";
   const styles = classNames(
     "inline-flex items-center rounded-lg py-4 px-8 text-body-reg transition transition-colors duration-150 text-center",
     {
@@ -34,33 +25,19 @@ function ButtonComponent(
       "bg-[transparent] text-primary border border-[transparent] hover:border-primary": variant === "text",
       "bg-[transparent] text-secondary border-secondary border hover:bg-secondary hover:text-primary":
         variant === "tertiary",
-      "bg-thunder-cloud text-dark-thunder-cloud hover:text-dark-thunder-cloud": disabled,
+      "bg-thunder-cloud text-dark-thunder-cloud hover:text-dark-thunder-cloud": componentProps.disabled,
       "cursor-pointer": as === "a",
     },
     className
   );
 
-  if (as === "a") {
-    const { children, ...linkProps } = props as ButtonAsLink;
-
-    return (
-      <a ref={ref as ForwardedRef<HTMLAnchorElement>} className={styles} {...linkProps}>
-        {leftIcon && <div className="inline pr-2">{leftIcon}</div>}
-        {children}
-        {rightIcon && <div className="inline pl-2">{rightIcon}</div>}
-      </a>
-    );
-  }
-
-  const { children, ...buttonProps } = props as ButtonAsButton;
-
   return (
-    <button ref={ref as ForwardedRef<HTMLButtonElement>} disabled={disabled} className={styles} {...buttonProps}>
+    <Component ref={ref} className={styles} {...componentProps}>
       {leftIcon && <div className="inline pr-2">{leftIcon}</div>}
       {children}
       {rightIcon && <div className="inline pl-2">{rightIcon}</div>}
-    </button>
+    </Component>
   );
-}
+};
 
-export const Button = React.forwardRef(ButtonComponent);
+export const Button: ButtonComponent = forwardRef(ButtonComponent);
diff --git a/packages/shared-ui/components/Card/Card.tsx b/packages/shared-ui/components/Card/Card.tsx
index b0710198..401245d3 100644
--- a/packages/shared-ui/components/Card/Card.tsx
+++ b/packages/shared-ui/components/Card/Card.tsx
@@ -1,31 +1,34 @@
 import classNames from "classnames";
 
 import { currencyFormatter } from "../../utils/currencyFormatter";
-import { UrlObject } from "url";
+import { PolymorphicComponentProps } from "../../uitls/polymorphicComponent";
 
-export interface CardProps {
+export interface BaseProps {
   title: string;
   price?: number;
-  Link?: React.ElementType;
   Image?: React.ElementType;
   subTitle?: string;
-  to: string | UrlObject;
-  className?: string;
   imageContainerClass?: string;
 }
 
-export const Card = ({
-  to,
+type CardProps<AsComponent extends React.ElementType> = PolymorphicComponentProps<AsComponent, BaseProps>;
+
+export const Card = <T extends React.ElementType>({
   subTitle,
   title,
   price,
-  Link = "a",
-  className = "",
+  as,
   imageContainerClass,
   children,
-}: React.PropsWithChildren<CardProps>) => {
+  ...linkProps
+}: React.PropsWithChildren<CardProps<T>>) => {
+  const RenderedLink = as || "a";
+
   return (
-    <Link href={to} className={`flex flex-col justify-center text-primary group w-full ${className}`}>
+    <RenderedLink
+      {...linkProps}
+      className={`flex flex-col justify-center text-primary group w-full ${linkProps.className}`}
+    >
       <span
         className={classNames(
           "rounded-xl group-hover:shadow-lg transition-shadow duration-150 overflow-hidden relative",
@@ -37,6 +40,6 @@ export const Card = ({
       <h2 className="text-h5 font-medium mt-4 mb-1">{title}</h2>
       {price && <span className="text-eyebrow font-bold">{currencyFormatter.format(price)}</span>}
       {subTitle && <span className="text-eyebrow">{subTitle}</span>}
-    </Link>
+    </RenderedLink>
   );
 };
diff --git a/packages/shared-ui/uitls/polymorphicComponent.ts b/packages/shared-ui/uitls/polymorphicComponent.ts
new file mode 100644
index 00000000..c13059ac
--- /dev/null
+++ b/packages/shared-ui/uitls/polymorphicComponent.ts
@@ -0,0 +1,57 @@
+// Taken from: https://www.benmvp.com/blog/forwarding-refs-polymorphic-react-component-typescript/
+
+// A more precise version of just React.ComponentPropsWithoutRef on its own
+export type PropsOf<
+  C extends keyof JSX.IntrinsicElements | React.JSXElementConstructor<any>
+> = JSX.LibraryManagedAttributes<C, React.ComponentPropsWithoutRef<C>>
+
+type AsProp<C extends React.ElementType> = {
+  /**
+   * An override of the default HTML tag.
+   * Can also be another React component.
+   */
+  as?: C
+}
+
+/**
+ * Allows for extending a set of props (`ExtendedProps`) by an overriding set of props
+ * (`OverrideProps`), ensuring that any duplicates are overridden by the overriding
+ * set of props.
+ */
+export type ExtendableProps<
+  ExtendedProps = {},
+  OverrideProps = {}
+> = OverrideProps & Omit<ExtendedProps, keyof OverrideProps>
+
+/**
+ * Allows for inheriting the props from the specified element type so that
+ * props like children, className & style work, as well as element-specific
+ * attributes like aria roles. The component (`C`) must be passed in.
+ */
+export type InheritableElementProps<
+  C extends React.ElementType,
+  Props = {}
+> = ExtendableProps<PropsOf<C>, Props>
+
+export type PolymorphicComponentProps<
+  C extends React.ElementType,
+  Props = {}
+> = InheritableElementProps<C, Props & AsProp<C>>
+
+/**
+ * Utility type to extract the `ref` prop from a polymorphic component
+ */
+export type PolymorphicRef<
+  C extends React.ElementType
+>
+ = React.ComponentPropsWithRef<C>['ref']
+
+/**
+ * A wrapper of `PolymorphicComponentProps` that also includes the `ref`
+ * prop for the polymorphic component
+ */
+export type PolymorphicComponentPropsWithRef<
+  C extends React.ElementType,
+  Props = {}
+>
+ = PolymorphicComponentProps<C, Props> & { ref?: PolymorphicRef<C> }
\ No newline at end of file