In this article i will explain you how to use different typescript types
\nIn typescript all the numbers are float by default, in javascript or typescript there is no difference between 5 and 5.0 they are all same
\nconst number = 5;\nconst number2 = 2.8;\nconst boolresult = true;\n\nif (boolresult) {\n console.log(\"Inside if\");\n}\nconst strresult = \"This is string constant variable\";\nIn all the above type typescript uses type inference to decide what type of variable based on the value we have assigned we can also manually define the type as below
\nconst number: number = 5;\nconst boolresult: boolean = true;\nconst strresult: string = \"This is string constant variable\";\nIn this example we are just telling typescript object that the variable is of type object
\nconst person: object = {\n name: \"Abc\",\n age: 50,\n hobbies: [\"sdfsd\"],\n role: [1, \"abc\"],\n};\nIn this example we are gonna tell typescript what is the type of properties that typescript object will hold
\nconst person1: {\n name: string;\n age: number;\n hobbies: string[];\n role: [number, string];\n} = {\n name: \"Abc\",\n age: 30,\n hobbies: [\"sdfsd\", \"sdfsdf\"],\n role: [1, \"abc\"],\n};\nIn this example typescript uses typeinference to detect what type of variable hobbies is
\nconst hobbies = [\"Cooking\", \"Singing\"];\nIn this we have manually tell the typescript that hobbies variable is of type array which holds string value
\nconst hobbies: string[] = [\"Cooking\", \"Singing\"];\nTuple is fixed length and fixed type array in typescript
\nIn this example you would notice that we have define the type inside array this mark that we will have only two element\nand they will be of type number and string
\nconst role: [number, string] = [1, \"abc\"];\nconst ADMIN = \"ADMIN\";\nconst AUTHOR = \"AUTHOR\";\nconst READ_ONLY = \"READ_ONLY\";\n\nenum ROLE {\n ADMIN,\n AUTHOR,\n READ_ONLY,\n}\n\nconsole.log(ROLE.ADMIN);\nAny type when used cancel the type check and can store any type of value inside variable for example
\nconst role: any[] = [\"Abc\", 1];\nUnion type variable helps us where we want any varibale to accept one or more type of values for example
\nconst uniontype: string | number | boolean = \"String var\";\nuniontype = 10;\nuniontype = true;\nconst literaltype: \"as-text\" | \"as-number\" = \"as-text\";\nIn below we have defined a type alias for our union type and we are refeering that alias in the constant variable
\ntype combinable = number | string | boolean;\n\nconst combinablevar: combinable = \"hello alias\";\ntype User = { name: string; age: number };\nconst u1: User = { name: \"abc\", age: 30 };\nIn this example we have defined function return type as a number
\nfunction add(n1: number, n2: number): number {\n return n1 + n2;\n}\nIn this example we have defined function return type as void
\nfunction printResult(num: number): void {\n console.log(\"Hello\" + num);\n}\nIn this example we are declaring a variable which is of type function
\nlet functiontype: Function;\nIn this example we have defined function types but we are specific about what type of argument it will recieve and\nwhat will be the return type
\nfunction add(n1: number, n2: number): number {\n return n1 + n2;\n}\nlet functiontype: (num1: number, num2: number) => number;\n\nfunctiontype = add(5, 2);\nfunction addAndHandler(n1: number, n2: number, cb: (num: number) => void) {\n const result = n1 + n2;\n cb(result);\n}\naddAndHandler(1, 2, (result) => {\n console.log(\"Result\", result);\n});\nIn unknown type we can store any type of values for example
\nlet unknowntype: unknown;\nunknowntype = 5;\nunknowntype = \"Abc\";\nThe difference between unknown type and any type is you cann't assign any other type variable to unknow type variable but in case of any you can
\nlet userInput: unknown;\nlet userName: string;\n\nuserInput = 5;\n\n//this will throw error as unknow type can be or cann't be of type string\n//but in case of any this will work\nuserName = userInput;\nGeneric type is a type which is connected with some other type
\nIn this example we have defined generic array type which hold string value
\n//generic way of defining\nconst names: Array<string | number | boolean> = [];\n\n//similar to above\nconst names: sting[] = [];\nIn this example we have defined a promise of generic type, we are sepcifying that this promise will return number type
\nconst promise: Promise<number> = new Promise((resolve, reject) => {\n setTimeout(() => {\n resolve(10);\n }, 2000);\n});\nIn this example we are defining a function which has generic type
\nfunction merge<T, U>(objA: T, objB: U) {\n return Object.assign(objA, objB);\n}\n\nconst mergeObj = merge<{ name: string; hobbies: string[] }, { age: number }>(\n { name: \"Max\", hobbies: [\"sdfsd\"] },\n { age: 30 }\n);\n