TypeScript - An Introduction
- 1. TypeScript
- 2. Hello! I am Hiten Pratap Singh I am here because I love to dive into new interesting things. You can find me at: https://github.com/hitenpratap/ https://hprog99.wordpress.com/ [email protected]
- 3. Agenda ▷ Introduction ▷ Installation ▷ Why TypeScript? ▷ Features ▷ Comparison With TypeScript Alternatives ▷ Who Uses TypeScript? ▷ Conclusion
- 5. “TypeScript lets you write JavaScript the way you really want to. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. Any browser. Any host. Any OS. Open Source.
- 6. Overview ▷ Syntax based on ECMAScript 4 & ECMASCript 6 proposals ▷ TS is first and foremost a superset of JS ▷ Any regular Javascript is valid TypeScript Code
- 7. “Microsoft's TypeScript may be the best of the many JavaScript front ends. It seems to generate the most attractive code.” - Douglas Crockford "CoffeeScript is to Ruby as TypeScript is to Java/C#/C++." - Luke Hoban
- 8. 2. Installation How to get it setup?
- 9. How To Install For more details check: https://www.typescriptlang.org/docs/tutorial.html Via npm (the Node.js package manager) By installing TypeScript’s Visual Studio plugins Just download any appropriate Visual Studio from Microsoft site and you are all set to go. You can also try Visual Studio Code IDE from https://code.visualstudio.com/ which is free, open source and available for multi-platform.
- 10. 3. Why TypeScript? Why everyone is using it more and more.
- 11. Main Goals of TypeScript ▷ Provide an optional type system for JavaScript. ▷ Provide planned features from future JavaScript editions to current JavaScript engines ▷ Modular Development
- 12. 4. Features What makes TypeScript super awesome
- 13. TypeScript Features ▷ Data Types Supported ▷ Optional Static Type Annotation ▷ Classes ▷ Interface ▷ Modules ▷ Arrow Expressions ▷ Type Assertions ▷ Ambient Declarations ▷ Source File Dependencies
- 14. Data Types
- 15. ▷ Any ▷ Primitive - Number - Boolean - String - Void - Null - Undefined - Same as JS ▷ Array ▷ Enum
- 16. Any is used when it’s impossible to determine the type Any
- 17. ▷ Doesn’t have separate integers and float/double type. These all are floating point values and get the type ‘number’ ▷ boolean - true/false value ▷ string - both single/double quote can be used ▷ No separate char type ▷ void - is used in function type returning nothing ▷ null and undefined - functions as usual Primitive
- 18. Array
- 19. By default, enums begin numbering their members starting at 0. You can change this by manually setting the value of one its members. Enum
- 20. Optional Types
- 22. Type Inference ▷ TypeScript tries to infer types ▷ Four ways to variable declaration - - Type and Value in one statement - Type but no Value then Value will be undefined - Value but on Type then the it will be of Any type but maybe be inferred based on its value. - Neither Value nor Type then Type will be Any and Value will be undefined.
- 23. Classes
- 24. ▷ Can implement interfaces ▷ Inheritance ▷ Instance methods/members ▷ Static methods/members ▷ Single constructor ▷ Default/Optional parameter ▷ ES6 class syntax TypeScript Classes
- 26. Inheritances
- 27. ▷ Declared using interface keyword ▷ Like other TS features it’s design time features i.e. no extra code would be emitted to resultant JS file ▷ Errors being shown when interface signature and implementation doesn’t match. TypeScript Interfaces
- 29. Modules
- 30. ▷ Modules can be defined using module keyword ▷ A module can contains sub-modules, class, enums or interfaces. But can’t directly contains functions. ▷ Modules can be nested(sub-modules). ▷ Classes and Interfaces can be exposed using export keyword. TypeScript Modules
- 33. ▷ Implicit return ▷ No braces for single expression ▷ Part of ES6 ▷ Lexically scoped this ▷ You don't need to keep typing function ▷ It lexically captures the meaning of arguments Arrow Expressions
- 35. Type Assertions
- 36. TypeScript's type assertion are purely you telling the compiler that you know about the types better than it does, and that it should not second guess you. Type Assertions
- 39. A major design goal of TypeScript was to make it possible for you to safely and easily use existing JavaScript libraries in TypeScript. TypeScript does this by means of declaration. Ambient Declarations
- 41. ▷ Can be done using reference keyword ▷ Must be the first statement of file ▷ Paths are relative to the current file ▷ Can also be done using tsconfig file Source File Dependencies
- 42. Source File Dependencies Example
- 44. ▷ Complete language + Runtime overhaul ▷ More features: generators, comprehensions, object literals etc ▷ Will take years before widely deployed ▷ No typing as of now(Maybe ES7) TypeScript VS ES6 Harmony
- 45. ▷ Also a superset to JavaScript ▷ More syntactic sugar, still dynamically typed ▷ Unlike TypeScript, JS is not valid CoffeeScript code ▷ It doesn’t track ECMAScript 6 TypeScript VS CoffeeScript
- 46. ▷ Optionally typed ▷ A native VM ▷ Operator overloading ▷ ECMAScript Dart spec ▷ Completely different syntax and semantics than JS TypeScript VS DART
- 49. 7. Conclusion
- 50. Pros: ▷ High value, low cost improvement over JavaScript ▷ Safer and more modular ▷ Solid path to ECMAScript 6 Cons: ▷ Still need to know some JS quirks ▷ Current compiler slowish(Faster one is in development) Conclusion
- 51. Thanks! Any questions? You can find me at: https://github.com/hitenpratap/ https://hprog99.wordpress.com/ [email protected]
- 52. References ▷ https://www.typescriptlang.org/docs/tutorial.html ▷ https://learnxinyminutes.com/docs/typescript/ ▷ https://basarat.gitbooks.io/typescript/content/ ▷ http://www.slideshare.net/SanderMak/typescript-coding-javascript- without-the-pain ▷ http://www.slideshare.net/aniruddha.chakrabarti/typescript-44668095