Typescript ppt

Typescript ppt

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  Typescript
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  • What's Typescript? •Type Annotation • Functions • Class • Inheritance • Module • Interface • Generics • Declaration source files (*.d.ts) • New features Agenda
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  • JavaScript isnot originally designed for large complex applications (mostly a scripting language, with functional programming constructs), lacks structuring mechanisms like Class, Module, Interface. • Typescript is a typed superset of JavaScript that compiles to plain JavaScript. • Adds additional features like Static Type (optional), Class, Module etc. to JavaScript • Microsoft technology. • Open Source. • Versions. • First made public in October 2012. • Latest version - Typescript 1.7. What’s Typescript?
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  • Any • AnyType is a super set of all types • var x : any; • var y; • Primitive • Number • Does not have separate integer and float/double type. • var num : number = 20; • var num = 20; • String • Both single quote or double quotes can be used. • var name : string = “hello”; • var name =’hello’; • Bool • var isOpen =true; Type Annotation
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  • Void • Usedas the return type of functions that don’t return any value • Object Types • class, interface, module. • Array • Array types can be written in: • var list: number[] = [1, 2, 3]; • var list: Array<number> = [1, 2, 3]; • var list:any[] = [1, true, "free"] • Enum • enum Color { Red, Green, Blue }; • var color = Color.Blue; Type Annotation
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  • Tuple • Tupletypes allow you to express an array where the type of a fixed number of elements is known. • var x: [string, number]; x = ['hello', 10]; Type Annotation
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  • Design timefeature. No additional code is emitted in the final JavaScript that TypeScript compiler produces. • If there’s a type mismatch TypeScript shows a warning. Type Annotation
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  • Type Annotationfor parameter and return type. • Optional and Default Parameter. • Function Overloads. • Fat Arrow functions. • Rest parameters. • denoted by ‘...argumentName’ for the last argument allow you to quickly accept multiple arguments in your function and get them as an array. Functions
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  • Properties andfields to store data • Methods to define behavior Class
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  • Typescript supportsinheritance of class through extends keyword • super keyword. Inheritance
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  • Modules canbe defined using module keyword. • A module can contain sub module, class, interface or enum. • Class, Interfaces , functions can be exposed using export keyword. • Adding file references. - /// <reference path=“filename.ts" /> Module
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  • Declared usinginterface keyword • TS compiler shows error when Interface signature and implementation does not match • Optional properties can be declared for an interface (using ?) Interface
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  • Able tocreate a component that can work over a variety of types rather than a single one. function identity<T>(arg: T): T { return arg; } • type argument inference - we want the compiler to set the value of T for us automatically based on the type of the argument we pass in. Generics
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  • The purposeof these files is to provide some typing information for JavaScript libraries. • These files do not compile to .js files, simply describe their JavaScript implementations, and act as their representative. • Contains typing info. • http://definitelytyped.org/ Declaration source files (*.d.ts)
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  • await &async • for..of – iteration. • Exponentiation operators - ** and **= • Spread operator New features