The TypeScript programming language is a superset of JavaScript that adds types to JavaScript using a set of tools called a type system. Primitive Types All “primitive”, or built-in data types in JavaScript are recognized by TypeScript. TypeScript Cheatsheet. Set of basic functionalities from TypeScript in one place. Cheatsheet was created by trainers for their students. Please note that some functionalities are part of ES201x but they are frequently used in TypeScript as well. Check also other Cheatsheets: Angular. Table of Contents. Types, variables and functions. View in the TypeScript Playground. Type Guarding: Sometimes Union Types solve a problem in one area but create another downstream.If A and B are both object types, A B isn't 'either A or B', it is 'A or B or both at once', which causes some confusion if you expected it to be the former. Quick cheat sheet with all the typings used for React forms. All the form elements events are the type React.ChangeEvent, where T is the HTML Element type. Here’s an example of all the different HTML types. For the event type is React.ChangeEvent. TypeScript is a typed language that allows you to specify the type of variables, function parameters, returned values, and object properties. Here an advanced TypeScript Types cheat sheet with examples. Sorry for the interrupt!
Responsive Single Page Applications (SPA) are gaining momentum to become the standard for enterprise web development. The most popular framework for delivering these applications is AngularJS. Introduced by Google several years ago, Angular is now in stable version 1.4 and 2.0 is on the horizon. The web developer community was surprised when the Angular team announced that the 2.0 version of their framework would be built using TypeScript, an open source superset of JavaScript introduced by Microsoft.
I wrote my first TypeScript “app” the day it was released in October 2012. Since then it has evolved to keep pace with the ECMAScript 6 specification and address issues and suggestions raised by the developer community. I’ve frequently presented and blogged about my use of Angular and TypeScript together. My first major project with TypeScript was a multi-million, multi-year project with an international team. After six months of developing using plain JavaScript and another data-binding library, the team decided to spike a proof-of-concept (POC) using Angular and TypeScript. We liked what we saw and made the switch. Several sprints later everyone was satisfied that we had made the right choice. By our best estimate, the combination improved productivity four times. That’s right – if I could deliver one story in a sprint, the change enabled me to deliver four stories of similar complexity.
I use this combination on current projects that are larger projects or have larger teams. Why so powerful? Angular and TypeScript complement each other. Angular itself provides:
- Expression parsing
- Glue for data-binding
- Declarative behaviors
- Dependency injection and logical containers for client components
- A powerful template engine
- Tools for logging, interacting with REST endpoints, routing, and more
- Testability out of the box
TypeScript complements Angular by helping large teams work with JavaScript. Its website explains it is designed for enterprise scale JavaScript applications. How does it help? Without compromising JavaScript’s flexibility (in other words, any valid JavaScript is valid TypeScript, and you are still able to take advantage of dynamic typing and other fundamental constructs), TypeScript enhances the language to provide powerful mechanisms such as class inheritance, interfaces, type descriptions, lambda expressions and generics. For a deeper dive into what this is and how this works, watch my presentation about Enterprise TypeScript.
I suggest you try out the combination today. Just because the new version of Angular will be built on TypeScript doesn’t mean you can’t use it with the existing version. In fact, the ability for TypeScript to “cover” existing modules through type definition libraries makes it very appealing to integrate into an existing project. I’ve found the JavaScript that TypeScript generates is clean and readable, so you are never “fully committed” to the technology – it’s always possible to take the generated JavaScript and use that as a baseline moving forward.
I’m pleased to present you with this simple, easy to use AngularJS 1.4.x and TypeScript 1.4 Cheat Sheet. It provides some easy links to grab the type definitions for Angular, shows you how common Angular features are mapped to interfaces and objects, and provides you with handy code snippets that illustrate how to declare controllers, define routes, and more using TypeScript. Your feedback and suggestions are welcome! Please download, print, and keep this handy next to your keyboard. Don’t hesitate to share this blog post with anyone else you know who may be using Angular with TypeScript today.
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TypeScript is the programming language which is the superset of JavaScript and compiles to plain JavaScript. TypeScript is also the general purpose object-oriented programming language with classes, object, and interfaces. The framework of JavaScript such as angular 2.0 is in TypeScript. JavaScript on the side of server and client complies the program created in TypeScript. Following programming cheat sheet helps a programmer to learn the syntax and various methods of the TypeScript programming language. You can find freelancers who know TypeScript language, and you also get certified freelancers for this language.
Simple Program of TypeScript
var message:string = “Hello World”
console.log(message)
Variable in TypeScript
The variables in the TypeScript follow the same rules of JavaScript. The variables in the TypeScript should not contain the spaces and special character except the underscore (_) and the dollar sign. The syntax of the variable in TypeScript includes the colon (:) after the variable name and also use the var keyword for a declaration of a variable.
Syntax for variable
Var name: string; In this syntax, the type of the variable is the string type, and the value of the variable is undefined.
var name: string = “Kitty” In this type variable store the particular name that is “kitty.”
Operators in TypeScript
Operators are the symbols that tell the compiler to perform the specific task. The operator works on data which is known as an operand. Following are the types of operators in Typescript.
Arithmetic Operators
Relational operators
Logical Operators
Bitwise Operators
Typescript Cheat Sheet Excel
Assignment Operators
String Operator
Type Operator
Conditional Operators
Typescript Return Two Types
Function in Typescript
The function is the block of code written in the program, and that block of code is maintainable and reusable in the whole program. The function is the collection of statements that perform the specific task.
Syntax for defining function
function function_name() {
// function body
}
Syntax for calling the function
function_name()
Syntax for returning function
function function_name():return_type {
//statements
return value;
}
Syntax for parameterised function
function func_name( param1 [:datatype], ( param2 [:datatype]) {
}
Numbers in TypeScript
The number class act as the wrapper and allows manipulation of numeric literals as were objects.
Syntax for Numbers
var var_name = new Number(value)
String in Typescript:
The object of the string will work with the characters. The primitive data types are wrap with the helper methods.
Syntax
var var_name = new String(string);
Following are the string method in TypeScript.
String Constructor Method
var str = new String( “This is string” );
console.log(“string constructor is:” + str.constructor)
String Length Method
var uname = new String(“Kitty Gupta”)
console.log(uname)
console.log(“Length “+uname.length)
String Prototype Method
function employee(id:number,name:string) {
this.id = id
this.name = name
Typescript Cheat Sheets
}
var emp = new employee(121,”Kitty”)
employee.prototype.email=”Kitty@xyz.com”
console.log(“Employee ‘s Id: “+emp.id)
console.log(“Employee’s name: “+emp.name)
console.log(“Employee’s Email ID: “+emp.email)
Array in TypeScript
The array is the collection of similar type of data structure. The array in the TypeScript allocates the sequential memory block. For declaration of an array use the var keyword. The unique integer called the subscript/index of the element recognizes the array elements. You can find freelancers who have knowledge of TypeScript language, and you also get certified freelancers for this language.
Syntax for the declaration and initialization of array
var array_name[:datatype]; //declaration
array_name = [val1,val2,valn..] //initialization
Tuples in TypeScript
In Typescript programming language tuples is the term which stores the multiple fields of different types. Through tuples you can also pass the parameters to functions.
Syntax
var tuple_name = [value1,value2,value3,…value n]
Union Types in TypeScript
Union types denote the values that can be one of the several types. The two or more data types are combined using the symbol(|) to denote the Union Type
Syntax for Union Type
Type1|Type2|Type3
Interface in TypeScript
The interface is the contact between the entity. The members of the interface are methods, events, and properties.
Following are the syntax for the interface.
interface interface_name {
}
Modules in TypeScript
The modules of TypeScript are of two types.
Internal module
Typescript Cheat Sheet 2019
The internal modules combined classes, functions, methods, and interfaces into the single unit and exported in another module. Following are the syntax for the internal module.
Syntax For Internal Modules.
module Freelancegig {
export function add(x, y) {
console.log(x+y);
}
}
External Module
This module is used to define load dependency between multiple external js files.
export interface SomeInterface {
//code declarations
}
Summary: This article is on the TypeScript programming cheat sheet. The TypeScript programming language is easily understandable if you know JavaScript programming language. The above programming cheat sheet helps a programmer to learn the syntax and various methods of the TypeScript programming language.
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