探索TypeScript：从JavaScript升级指南

需积分: 12 184 浏览量更新于2024-07-14 收藏 813KB PDF 举报

"Tackling TypeScript 2020.6.pdf" 是一本关于TypeScript的书籍，由Dr. Axel Rauschmayer撰写，涵盖了从JavaScript升级到TypeScript的相关内容。本书首先介绍了预览部分的基本信息，包括： 1. 关于这本书：这是一本关于TypeScript的指南，旨在帮助读者理解和使用这种强类型编程语言。 2. 内容概述：书中详细讲解了TypeScript的工作原理、项目结构、IDE的使用以及如何从JavaScript迁移到TypeScript等主题。 3. 购书福利：购买本书可以获得作者提供的详细内容和指导。 4. 预览内容：读者可以通过特定渠道预览书中的部分内容。 5. 错误报告：鼓励读者发现错误并提供反馈。 6. 符号注释：书中使用图标标记的笔记有助于读者识别不同类型的信息。 7. 致谢：作者对支持他创作的人表示感谢。接着，书中探讨了为什么选择TypeScript的原因： 1. 使用TypeScript的好处：包括静态类型检查、更好的工具支持、代码可维护性和可扩展性等。 2. 使用TypeScript的缺点：可能的学习曲线、编译时的额外步骤和可能的性能影响等。 3. TypeScript的误区：澄清了一些关于TypeScript的误解。此外，书中还提供了免费的TypeScript资源信息，以供读者进一步学习和探索。在技术部分，书中引导读者入门TypeScript： 1. TypeScript的工作原理：从宏观层面解释TypeScript项目的构成，包括源代码、类型定义和其他编译产物。 2. 通过集成开发环境(IDE)编程：介绍如何利用IDE提高TypeScript的开发效率。 3. 其他编译产出：讨论TypeScript编译后生成的其他文件，如JavaScript代码和元数据文件。 "Tackling TypeScript 2020.6.pdf"是针对JavaScript开发者的一份全面指南，旨在帮助他们理解并熟练使用TypeScript，提升开发效率和代码质量。书中内容深入浅出，结合实际案例和工具使用，适合不同层次的开发者阅读。

14 1 About this book

2.2 The downsides of using TypeScript 17

also check code for consistency and generate type deﬁnitions. For more information, see

chapter “Type Checking JavaScript Files” in the TypeScript handbook.

2.1.5 TypeScript makes refactorings safer

Refactorings are automated code transformations that many integrated development en-

vironments offer.

Renaming methods is an example of a refactoring. Doing so in plain JavaScript can be

tricky because the same name might refer to different methods. TypeScript has more

information on how methods and types are connected, which makes renaming methods

safer there.

2.1.6 TypeScript can compile new features to older code

TypeScript tends to quickly support ECMAScript stage 4 features (such features are

scheduled to be included in the next ECMAScript version). When we compile to

JavaScript, the compiler option --target lets us specify the ECMAScript version that

the output is compatible with. Then any incompatible feature (that was introduced

later) will be compiled to equivalent, compatible code.

Note that this kind of support for older ECMAScript versions does not require TypeScript

or static typing: The JavaScript compiler Babel does it too, but it compiles JavaScript to

JavaScript.

2.2 The downsides of using TypeScript

• It is an added layer on top of JavaScript: more complexity, more things to learn,

etc.

• It introduces a compilation step when writing code.

• npm packages can only be used if they have static type deﬁnitions.

– These days, many packages either come with type deﬁnitions or there are

type deﬁnitions available for them on DeﬁnitelyTyped. However, especially

the latter can occasionally be slightly wrong, which leads to issues that you

don’t have without static typing.

• Getting static types right is occasionally difﬁcult. My recommendation here is to

keep things as simple as possible – for example: Don’t overdo generics and type

variables.

2.3 TypeScript myths

2.3.1 TypeScript code is heavyweight

TypeScript code can be very heavyweight. But it doesn’t have to be. For example, due to

type inference, we can often get away with few type annotations:

function selectionSort(arr: number[]) { // (A)

for (let i=0; i<arr.length; i++) {

const minIndex = findMinIndex(arr, i);

剩余229页未读，继续阅读

qq_30418147

粉丝: 0
资源: 1

探索TypeScript：从JavaScript升级指南

Apress.More.iPhone.3.Development.Tackling.iPhone.SDK.3.Dec.2009.rar

More.iPhone.3.Development.Tackling.iPhone.SDK.3.Dec.2009.pdf

[iPhone开发书籍大全].More.iPhone.3.Development.Tackling.iPhone.SDK.3(Apress.2009-12).pdf

Domain.Driven.Design.Tackling.Complexity.In.The.Heart.Of.Software.rar

addison.wesley.domain.driven.design.tackling.complexity.in.the.heart.of.software.rar

Tackling Procrastination It’s easier and more valuable than you think.pdf

Domain-Driven Design –Tackling Complexity in the Heart of Software.pdf

Bioinformatics.Data.Skills.Reproducible.and.Robust.Research.pdf

Jenkins Essentials.pdf

Practical Flutter.pdf

最新资源