April 2025
Intermediate to advanced
422 pages
9h 33m
Portuguese (Portugal, Brazil)
Content preview from Livro de receitas do TypeScript
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Capítulo 2. Tipos básicos
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Agora que já tens tudo pronto, está na altura de escreveres TypeScript! Começar deve ser fácil, mas em breve irás deparar-te com situações em que não tens a certeza se estás a fazer a coisa certa. Deves usar interfaces ou type aliases? Deves fazer anotações ou deixar a inferência de tipos fazer a sua magia? E quanto a any e unknown: é seguro usá-los? Algumas pessoas na Internet disseram que nunca as devias usar, então porque é que fazem parte doTypescript?
Todas essas perguntas serão respondidas neste capítulo. Veremos os tipos básicos que compõem o TypeScript e aprenderemos como um desenvolvedor de TypeScript experiente os usará. Podes usar isto como uma base para os próximos capítulos, para que tenhas uma ideia de como o compilador TypeScript chega aos seus tipos e como interpreta as tuasanotações.
Isto é sobre a interação entre o teu código, o editor e o compilador. E trata de subir e descer na hierarquia de tipos, como veremos na Receita 2.3. Quer sejas um programador experiente de Typescript ou estejas apenas a começar, encontrarás informações úteis neste capítulo.
2.1 Anotar eficazmente
Problema
Anotar tipos é complicado e aborrecido.
Solução
Anota apenas quando quiseres que os teus tipos sejam verificados.
Debate
Uma anotação de tipo é uma maneira de dizer explicitamente quais tipos esperar. Sabes, as coisas proeminentes ...
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I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.