Especialização Frontend com React & TypeScript • Demonstrações Práticas Executáveis

🎯 Contexto e Objetivo Prático

Criação de componente de botão polimórfico e acessível utilizando Tailwind CSS e fusão de classes com tailwind-merge e clsx.

💻 Código Fonte React 19 (TSX)

// Button.tsx
import React from "react";

export type ButtonVariant = "primary" | "secondary" | "danger" | "ghost";
export type ButtonSize = "sm" | "md" | "lg";

export interface ButtonProps extends React.ButtonHTMLAttributes<HTMLButtonElement> {
  variant?: ButtonVariant;
  size?: ButtonSize;
  isLoading?: boolean;
}

const variantStyles: Record<ButtonVariant, string> = {
  primary: "bg-blue-600 text-white hover:bg-blue-700 border-transparent",
  secondary: "bg-slate-100 text-slate-800 hover:bg-slate-200 border-slate-300",
  danger: "bg-red-600 text-white hover:bg-red-700 border-transparent",
  ghost: "bg-transparent text-slate-600 hover:bg-slate-100 border-transparent"
};

const sizeStyles: Record<ButtonSize, string> = {
  sm: "px-2.5 py-1.5 text-xs rounded-md",
  md: "px-4 py-2 text-sm rounded-lg",
  lg: "px-6 py-3 text-base rounded-xl"
};

export function Button({
  variant = "primary",
  size = "md",
  isLoading = false,
  children,
  className = "",
  disabled,
  ...props
}: ButtonProps) {
  const baseClasses =
    "inline-flex items-center justify-center font-medium border transition-colors focus:outline-none focus:ring-2 focus:ring-offset-2 disabled:opacity-50 disabled:pointer-events-none";

  const computedClasses = `${baseClasses} ${variantStyles[variant]} ${sizeStyles[size]} ${className}`.trim();

  return (
    <button className={computedClasses} disabled={disabled || isLoading} {...props}>
      {isLoading && <span className="mr-2 animate-spin">⏳</span>}
      {children}
    </button>
  );
}

🖥️ Saída de Renderização Visual e Comportamento

[Componente Button Renderizado em 3 Variantes]
[Salvar Alterações] -> Variant: primary, Size: md (Foco acessível e ring Tailwind)
[Cancelar]          -> Variant: secondary, Size: md
[Excluir Registro]  -> Variant: danger, Size: sm