Online Javascript to Typescript Converter
This is a utility tool to convert a JavaScript codebase to TypeScript, while trying to solve some of the
common TypeScript errors that will be received upon such a conversion.
Basic variable types
Type |
Example |
Notes |
number |
let myNumber: number = 6 |
Represent all numbers : integer, float, hex etc. |
string |
let fullName: string = Bob Bobbington |
Text with all text functions (indexOf, replace etc.) |
boolean |
let isTrue: boolean = true |
true/false value |
Array |
let list: Array = [1, 2, 3] |
Shorter version: let list: number[] = [1, 2, 3]; |
Tuple |
let x: [string, number] = ['test', 2]; |
Array contains ains items with various types |
any |
let x: any = 2; |
Everything can be assigned to value with any type |
Enum |
enum Color {Red, Blue } |
Usage: let c: Color = Color.Blue; |
Never |
function fail(): never {while(true) {}} |
Indicating that something never should happen |
Null or undefined |
let u: undefined = undefined; |
In TS there is dedicated type for null and undefined |
Object |
let x:Object = {id: 2}; |
Represents any object |
Function |
let myFn:Function = function() {...} |
Represents any function |
Functions
Concept |
Code |
Function |
{ (arg1 :Type, argN :Type) :Type; } or (arg1 :Type, argN :Type) => Type; |
Constructor |
{ new () :ConstructedType; } or new () => ConstructedType; |
Function type with optional param |
(arg1 :Type, optional? :Type) => ReturnType; |
Function type with rest param |
(arg1 :Type, ...allOtherArgs :Type[]) => ReturnType; |
Function type with static property |
{ () :Type; staticProp :Type; } |
Default argument |
function fn(arg1 :Type = 'default') :ReturnType {} |
Arrow function |
(arg1 :Type) :ReturnType =>; {} or (arg1 :Type) :ReturnType =>; Expression |
rimitive Types
Type |
Code |
Any type (explicitly untyped) |
any |
void type (null or undefined, use for function returns only) |
void |
String |
string |
Number |
number |
Boolean |
boolean |