TypeScript supports callback functions to make your program asynchronous. A callback function is a function which is scheduled to be called after some asynchronous processing is completed.
TypeScript Function or Method Overloading
In TypeScript, function overloading, or method overloading, is the ability to create multiple methods with the same name and a different number of parameters or types.
TypeScript Functions – REST, Optional and Default Parameters
Learn to create functions, function type declaration, optional parameters, default parameters and rest parameters with example. Table of Contents Create function Function Types Optional Parameters Default Parameters Rest Parameters Create function In TypeScript, you can create functions in two ways. Function Declarations These are named functions written in traditional JavaScript style. Function Expressions These functions […]
TypeScript Template Strings
A template string is a regular JavaScript string which is enclosed with back-tick characters (`) seeded with placeholders denoted with ${ }. At runtime, your code replaces the placeholders with real values. Template String Example Let’s see a very basic example of template string. In this example, at runtime, the code replaces placeholders with the […]
Set in TypeScript
Set is a new data structure introduced in ES6. It allows to store distinct values into a List. Learn to create set, add and iterate set values.
Map in TypeScript
Map is a new data structure introduced in ES6, to store key-value pairs. Learn to create map, add, delete, retrieve and iterate over Map entries.
TypeScript ‘for…of’ Loop
In TypeScript, You can iterate over iterable objects (including array, map, set, string, arguments object and so on) using for…of loop. To be an iterable, an object must implement the @@iterator method.
tsconfig.json – TypeScript Compiler Configuration
TypeScript compiler uses tsconfig.json to get configuration options for generating JavaScript code from TypeScript sourcecode. When you uses $ tsc command to compile TypeScript code, compiler searches for configurations loaded in tsconfig.json.
String Literal Types
In TypeScript, string literals allow you to specify the exact value a string must have in it’s lifespan. You can assume it a form as ‘string based enum’ which also is named group of string constants.
Enums in TypeScript
In TypeScript, enums are set of named constants. Though it is optional, but enums should be a named group of related constants. TypeScript supports both traditional enums and string-based enums.
Arrays in TypeScript
Learn to create array, clone array, merge arrays and iterate through array elements in TypeScript with easy to follow examples.
undefined vs null in JavaScript
A variable is said to be “undefined” if it has been declared but not initialized. Whereas “null” is assigned to a variable whose value is absent at that moment. In simple words, when you do not assign value to a variable, JavaScript engine treats it as undefined. The null value is assigned by programmer to […]
TypeScript Union Types
In TypeScript, you can define a variable which can have multiple types of values (i.e. number, string etc). This is called union type. A union type allows us to define a variable with multiple types. This is achieved by using the pipe (‘|’) symbol between the types. Union types helps in some situations when migrating […]
Equals Operator ( == ) vs Strict Equals Operator ( === )
In TypeScript (and JavaScript), you can compare with either equality operator (‘==’) or strict equality operator (‘===’). Both seems almost similar; but the way they compare two values is very different. Equals Operator ( == ) The comparison x == y with equals operator, where x and y are values, produces true or false. The […]
Spread Operator in TypeScript
In TypeScript, the spread operator (in form of ellipsis) can be used to initialize arrays and objects from another array or object. You can also use spread operator for object destructuring. Spread Operator vs. apply() Method The JavaScript’s apply() method calls a function with a given this value, and arguments provided as an array. e.g. […]
TypeScript Logical Operators
TypeScript logical operators are similar what you learn in JavaScript logical operators. These operators help in comparing boolean expressions and producing single boolean value as result. Logical Operators Operator Description Logical AND operator – && If both operands (or expressions) are true, then result will be true, else false. Read More: Truthy and Falsy Logical […]
TypeScript Comparison Operators
TypeScript comparison operators are same as JavaScript. Comparison operators help in comparing two variables by it’s values. Please note that some operators uses type coercion while comparing the values, while some not. Please use them carefully. Type coercion means that when the operands of an operator are different types, one of them will be converted […]
TypeScript Types
TypeScript supports type checking for basic types (primitives and object types). It also supports generics, decorators and ES6 module types as well. It is important to learn that the type system in typescript is designed to be optional. So all javascript programs are typescript programs as well. Table of Contents Static types – Primitive Types […]
TypeScript Tutorial
TypeScript is an open source programming language that is developed and maintained by Microsoft in 2012. TypeScript brings ‘types’ (or datatypes) to JavaScript. Generally, types check the validity of the supplied values, before they are stored or manipulated by the program. This ensures that the code behaves as expected and prevent you to accidentally corrupt […]
TypeScript Arithmetic Operators
An operator is a symbol that represents a specific action. An arithmetic operator can be used with one or more than values to produce a single value. In typescript, we can perform arithmetic operations using below given 10 operators. Arithmetic operators Operator Name Description and Example x + y Addition Adds two operands. x – […]