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    <title>DEV Community: Arthur Freitas</title>
    <description>The latest articles on DEV Community by Arthur Freitas (@arthursfreitas).</description>
    <link>https://dev.to/arthursfreitas</link>
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      <title>DEV Community: Arthur Freitas</title>
      <link>https://dev.to/arthursfreitas</link>
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    <item>
      <title>Dominando o Design Pattern Facade: Simplifique a Integração de Sistemas!</title>
      <dc:creator>Arthur Freitas</dc:creator>
      <pubDate>Sun, 25 Feb 2024 11:00:00 +0000</pubDate>
      <link>https://dev.to/arthursfreitas/dominando-o-design-pattern-facade-simplifique-a-integracao-de-sistemas-2i6d</link>
      <guid>https://dev.to/arthursfreitas/dominando-o-design-pattern-facade-simplifique-a-integracao-de-sistemas-2i6d</guid>
      <description>&lt;h2&gt;
  
  
  Descomplicando Integrações com o Design Pattern Facade
&lt;/h2&gt;

&lt;p&gt;Saudações, Devs! 👋 Hoje vamos explorar o &lt;strong&gt;Design Pattern Facade&lt;/strong&gt;, mostrando como ele pode ser eficaz para simplificar a comunicação com operações complexas e externas e internas, como o processamento de pagamentos em plataformas de terceiros.&lt;/p&gt;

&lt;h3&gt;
  
  
  O Que Torna o Facade Tão Impactante? 🧠
&lt;/h3&gt;

&lt;p&gt;O &lt;strong&gt;Design Pattern Facade&lt;/strong&gt; é crucial por vários motivos, especialmente quando lidamos com integrações externas:&lt;/p&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Simplificar a comunicação&lt;/strong&gt;: Facilita a interação com APIs de pagamento complexas e diversas.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Diminuir o acoplamento&lt;/strong&gt;: Reduz a dependência do código cliente com APIs externas, permitindo fácil substituição ou adição de novos serviços de pagamento.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Facilitar modificações&lt;/strong&gt;: Permite adaptar-se rapidamente a mudanças nas APIs de pagamento sem grandes alterações no código base.&lt;/li&gt;
&lt;/ul&gt;

&lt;h3&gt;
  
  
  Implementação Prática em TypeScript: Processamento de Pagamentos 📝
&lt;/h3&gt;

&lt;p&gt;Vamos adaptar nosso cenário para incluir a comunicação com softwares de pagamento externos, como Stripe, PayPal, e serviços bancários para transferências.&lt;/p&gt;

&lt;h4&gt;
  
  
  Passo 1. Definindo Interfaces de Métodos de Pagamento
&lt;/h4&gt;

&lt;p&gt;Adaptamos nossa interface para refletir a comunicação com serviços externos:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kr"&gt;interface&lt;/span&gt; &lt;span class="nx"&gt;ExternalPaymentService&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="nb"&gt;Promise&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Passo 2: Implementações Concretas para Comunicação com Serviços Externos
&lt;/h3&gt;

&lt;p&gt;Implementamos adaptadores para cada serviço externo de pagamento:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;StripePaymentService&lt;/span&gt; &lt;span class="k"&gt;implements&lt;/span&gt; &lt;span class="nx"&gt;ExternalPaymentService&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="nb"&gt;Promise&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="c1"&gt;// Lógica para processar o pagamento via Stripe&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="s2"&gt;`Pagamento de &lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt; processado com sucesso via Stripe.`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;PaypalPaymentService&lt;/span&gt; &lt;span class="k"&gt;implements&lt;/span&gt; &lt;span class="nx"&gt;ExternalPaymentService&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="nb"&gt;Promise&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="c1"&gt;// Lógica para processar o pagamento via PayPal&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="s2"&gt;`Pagamento de &lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt; processado com sucesso via PayPal.`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;BankTransferService&lt;/span&gt; &lt;span class="k"&gt;implements&lt;/span&gt; &lt;span class="nx"&gt;ExternalPaymentService&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="nb"&gt;Promise&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="c1"&gt;// Lógica para processar o pagamento via Transferência Bancária&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="s2"&gt;`Pagamento de &lt;/span&gt;&lt;span class="p"&gt;${&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt;&lt;span class="s2"&gt; processado com sucesso via Transferência Bancária.`&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Passo 3: Criando a Fachada de Pagamento
&lt;/h3&gt;

&lt;p&gt;Agora, criamos uma fachada que encapsula a complexidade de escolher e chamar o método de pagamento apropriado:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;PaymentIntegrationFacade&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;private&lt;/span&gt; &lt;span class="nx"&gt;paymentServices&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="p"&gt;{[&lt;/span&gt;&lt;span class="nx"&gt;key&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;]:&lt;/span&gt; &lt;span class="nx"&gt;ExternalPaymentService&lt;/span&gt;&lt;span class="p"&gt;}&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="na"&gt;stripe&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;StripePaymentService&lt;/span&gt;&lt;span class="p"&gt;(),&lt;/span&gt;
    &lt;span class="na"&gt;paypal&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;PaypalPaymentService&lt;/span&gt;&lt;span class="p"&gt;(),&lt;/span&gt;
    &lt;span class="na"&gt;bankTransfer&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;BankTransferService&lt;/span&gt;&lt;span class="p"&gt;(),&lt;/span&gt;
  &lt;span class="p"&gt;};&lt;/span&gt;

  &lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;method&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="nb"&gt;Promise&lt;/span&gt;&lt;span class="o"&gt;&amp;lt;&lt;/span&gt;&lt;span class="kr"&gt;string&lt;/span&gt;&lt;span class="o"&gt;&amp;gt;&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;service&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;paymentServices&lt;/span&gt;&lt;span class="p"&gt;[&lt;/span&gt;&lt;span class="nx"&gt;method&lt;/span&gt;&lt;span class="p"&gt;];&lt;/span&gt;
    &lt;span class="k"&gt;if &lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="o"&gt;!&lt;/span&gt;&lt;span class="nx"&gt;service&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
      &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;Método de pagamento inválido.&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
    &lt;span class="p"&gt;}&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;service&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Passo 4: Utilizando a Nova Fachada
&lt;/h3&gt;

&lt;p&gt;Agora, a fachada gerencia a complexidade de interagir com diferentes plataformas de pagamento:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;paymentIntegrationFacade&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;PaymentIntegrationFacade&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;

&lt;span class="c1"&gt;// Exemplos de chamadas&lt;/span&gt;
&lt;span class="k"&gt;async&lt;/span&gt; &lt;span class="kd"&gt;function&lt;/span&gt; &lt;span class="nf"&gt;executePayment&lt;/span&gt;&lt;span class="p"&gt;()&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;paymentIntegrationFacade&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;stripe&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;100&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt; &lt;span class="c1"&gt;// Stripe&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;paymentIntegrationFacade&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;paypal&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;200&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt; &lt;span class="c1"&gt;// PayPal&lt;/span&gt;
  &lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;await&lt;/span&gt; &lt;span class="nx"&gt;paymentIntegrationFacade&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;processPayment&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="s1"&gt;bankTransfer&lt;/span&gt;&lt;span class="dl"&gt;'&lt;/span&gt;&lt;span class="p"&gt;,&lt;/span&gt; &lt;span class="mi"&gt;300&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt; &lt;span class="c1"&gt;// Transferência Bancária&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="nf"&gt;executePayment&lt;/span&gt;&lt;span class="p"&gt;();&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Conclusão
&lt;/h3&gt;

&lt;p&gt;Este exemplo demonstra o poder do Design Pattern Facade em proporcionar uma interface simplificada para operações complexas, como o processamento de pagamentos.&lt;/p&gt;

&lt;p&gt;Espero que este guia inspire suas próximas implementações, elevando a eficiência e a clareza do seu código. Até mais, Devs! 🚀&lt;/p&gt;

</description>
      <category>facade</category>
      <category>programming</category>
      <category>typescript</category>
      <category>designpatterns</category>
    </item>
    <item>
      <title>Domine o Design Pattern Strategy: Simplifique Seus Códigos!</title>
      <dc:creator>Arthur Freitas</dc:creator>
      <pubDate>Sat, 24 Feb 2024 18:56:07 +0000</pubDate>
      <link>https://dev.to/arthursfreitas/domine-o-design-pattern-strategy-simplifique-seus-codigos-380p</link>
      <guid>https://dev.to/arthursfreitas/domine-o-design-pattern-strategy-simplifique-seus-codigos-380p</guid>
      <description>&lt;h2&gt;
  
  
  Simplificando o Desenvolvimento com o Design Pattern Strategy
&lt;/h2&gt;

&lt;p&gt;Olá, Devs! 👋 Hoje, vamos mergulhar em um dos conceitos mais transformadores no mundo da programação: o &lt;strong&gt;Design Pattern Strategy&lt;/strong&gt;, e vamos explorar como aplicá-lo de maneira eficaz usando &lt;strong&gt;TypeScript&lt;/strong&gt;.&lt;/p&gt;

&lt;h2&gt;
  
  
  Entendendo o Design Pattern Strategy 🧠
&lt;/h2&gt;

&lt;p&gt;O &lt;strong&gt;Design Pattern Strategy&lt;/strong&gt; é um padrão comportamental que nos permite definir uma família de algoritmos, encapsulá-los como objetos e torná-los intercambiáveis. A beleza desse padrão está em sua capacidade de permitir que o algoritmo mude independentemente dos clientes que o utilizam.&lt;/p&gt;

&lt;h2&gt;
  
  
  Por Que Strategy É Um Game-Changer? 🚀
&lt;/h2&gt;

&lt;ul&gt;
&lt;li&gt;
&lt;strong&gt;Flexibilidade&lt;/strong&gt;: Troque algoritmos sem mexer no código cliente.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Desacoplamento&lt;/strong&gt;: Separa o que faz de como faz.&lt;/li&gt;
&lt;li&gt;
&lt;strong&gt;Manutenibilidade&lt;/strong&gt;: Facilita significativamente a expansão e manutenção dos algoritmos.&lt;/li&gt;
&lt;/ul&gt;

&lt;h2&gt;
  
  
  Demonstração Prática com TypeScript 📝
&lt;/h2&gt;

&lt;p&gt;Imagine um cenário: uma loja online precisa aplicar diferentes estratégias de desconto com base no tipo de cliente. Vamos ver como o Strategy Pattern pode simplificar isso:&lt;/p&gt;

&lt;h3&gt;
  
  
  1. Definindo a Interface de Estratégia
&lt;/h3&gt;

&lt;p&gt;Primeiro, criamos uma interface para nossas estratégias de desconto:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kr"&gt;interface&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nf"&gt;applyDiscount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Passo 2: Implementar Estratégias Concretas
&lt;/h3&gt;

&lt;p&gt;Agora, implementamos estratégias de desconto específicas:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;NoDiscount&lt;/span&gt; &lt;span class="k"&gt;implements&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nf"&gt;applyDiscount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;SeasonalDiscount&lt;/span&gt; &lt;span class="k"&gt;implements&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nf"&gt;applyDiscount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;amount&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.9&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="c1"&gt;// 10% de desconto&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;

&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;LoyaltyDiscount&lt;/span&gt; &lt;span class="k"&gt;implements&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="nf"&gt;applyDiscount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="nx"&gt;amount&lt;/span&gt; &lt;span class="o"&gt;*&lt;/span&gt; &lt;span class="mf"&gt;0.8&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt; &lt;span class="c1"&gt;// 20% de desconto&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Passo 3: Contexto para Utilizar Estratégias
&lt;/h3&gt;

&lt;p&gt;Criamos um contexto que utiliza uma estratégia de desconto:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;class&lt;/span&gt; &lt;span class="nc"&gt;DiscountContext&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
  &lt;span class="k"&gt;private&lt;/span&gt; &lt;span class="nx"&gt;strategy&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;

  &lt;span class="nf"&gt;constructor&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;strategy&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;strategy&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;strategy&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;

  &lt;span class="nf"&gt;setStrategy&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;strategy&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="nx"&gt;DiscountStrategy&lt;/span&gt;&lt;span class="p"&gt;)&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;strategy&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="nx"&gt;strategy&lt;/span&gt;&lt;span class="p"&gt;;&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;

  &lt;span class="nf"&gt;calculate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;:&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt;&lt;span class="p"&gt;):&lt;/span&gt; &lt;span class="kr"&gt;number&lt;/span&gt; &lt;span class="p"&gt;{&lt;/span&gt;
    &lt;span class="k"&gt;return&lt;/span&gt; &lt;span class="k"&gt;this&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nx"&gt;strategy&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;applyDiscount&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;amount&lt;/span&gt;&lt;span class="p"&gt;);&lt;/span&gt;
  &lt;span class="p"&gt;}&lt;/span&gt;
&lt;span class="p"&gt;}&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Passo 4: Aplicar Estratégias
&lt;/h3&gt;

&lt;p&gt;Por fim, aplicamos diferentes estratégias de desconto baseadas na necessidade:&lt;br&gt;
&lt;/p&gt;

&lt;div class="highlight js-code-highlight"&gt;
&lt;pre class="highlight typescript"&gt;&lt;code&gt;&lt;span class="kd"&gt;const&lt;/span&gt; &lt;span class="nx"&gt;discountContext&lt;/span&gt; &lt;span class="o"&gt;=&lt;/span&gt; &lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;DiscountContext&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;NoDiscount&lt;/span&gt;&lt;span class="p"&gt;());&lt;/span&gt;
&lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;discountContext&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;calculate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;100&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt; &lt;span class="c1"&gt;// Sem desconto: 100&lt;/span&gt;

&lt;span class="nx"&gt;discountContext&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;setStrategy&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;SeasonalDiscount&lt;/span&gt;&lt;span class="p"&gt;());&lt;/span&gt;
&lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;discountContext&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;calculate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;100&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt; &lt;span class="c1"&gt;// Desconto sazonal: 90&lt;/span&gt;

&lt;span class="nx"&gt;discountContext&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;setStrategy&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="k"&gt;new&lt;/span&gt; &lt;span class="nc"&gt;LoyaltyDiscount&lt;/span&gt;&lt;span class="p"&gt;());&lt;/span&gt;
&lt;span class="nx"&gt;console&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;log&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="nx"&gt;discountContext&lt;/span&gt;&lt;span class="p"&gt;.&lt;/span&gt;&lt;span class="nf"&gt;calculate&lt;/span&gt;&lt;span class="p"&gt;(&lt;/span&gt;&lt;span class="mi"&gt;100&lt;/span&gt;&lt;span class="p"&gt;));&lt;/span&gt; &lt;span class="c1"&gt;// Desconto de fidelidade: 80&lt;/span&gt;
&lt;/code&gt;&lt;/pre&gt;

&lt;/div&gt;



&lt;h3&gt;
  
  
  Conclusão
&lt;/h3&gt;

&lt;p&gt;Com este simples exemplo, você pode ver como o Design Pattern Strategy permite a flexibilidade e a expansão de seus códigos de maneira limpa e organizada.&lt;/p&gt;

&lt;p&gt;Palavras-chave: Design Pattern Strategy, TypeScript, Padrões de Projeto, Flexibilidade de Código, Desacoplamento, Manutenibilidade, Estratégias de Desconto, Práticas de Codificação.&lt;/p&gt;

&lt;p&gt;Espero que este post tenha esclarecido o padrão Strategy e como implementá-lo em TypeScript. Até a próxima, Devs! 🚀&lt;/p&gt;

</description>
      <category>programming</category>
      <category>typescript</category>
      <category>designpatterns</category>
      <category>strategy</category>
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