Differences Between TypeScript Type vs Interface
TypeScript is an open-source scripting language used for application development. The typescript trans piles to JavaScript and it is referred to as a superset of JavaScript. TypeScript compiler named ‘tsc’ written in typescript only and it is compiled to JavaScript as well. TypeScript is mainly used for developing both client-side and server-side javascript applications. An interface can be extended by other interfaces. TypeScript also allows the interface to inherit from multiple interfaces. An interface can be inherited in two ways that are Single interface inheritance and multiple interface inheritance. An interface is part of typescript only an interface can’t be converted to JavaScript.
Let us study much more about TypeScript vs Interface in detail:
The typescript was designed and developed by Microsoft in the year 2012. TypeScript has three components that are language, the typescript compiler, typescript language service (TLS). The language referred to syntax, keywords and type annotations. A compiler converts the instructions into javascript which is written in typescript. TLS is used to support a common set of typical editor operations like statement completion, code formatting, etc. TypeScript extending its functionalities with other libraries like Node.js, D3.js, JQuery, etc. Typescript follows its own syntax as it declares the data type of variable next to a variable name.
TypeScript has a lot of features like compile-time checking, type inference, type erasure, interfaces, enumerated type, generic, namespaces, tuple, await, classes, modules, optional or default parameters, anonymous functions. It is more scalable and we can build robust components. It is independent of platform, browser and operating system also. It presents the method for the developer to express variables, arrays, and properties in a non-standard javascript way.
TypeScript is superior to other scripting languages comparatively like Dart. TypeScript does not require a specific environment setup for the execution. It can be run where JavaScript can run easily. The benefits of using the typescript are that it will compile the code and check the compilation errors. It also finds the syntax error and tells before the running of the script. TypeScript has a feature of optional static typing and types inference system through the typescript language service(TLS). The type of variable can be inferred by language service (TLS) based on its value if a type is not declared for the variable.
TypeScript types have a different set of types and values supported by the language. Types will check the allocated values to variables before storing it or executed for the application. Type can be of three types: 1. Any type: – By using any data type, it means type checking for a variable cannot be done. 2. Built-in type: – the data types which are already there in a system like a number, string, boolean, void, null and undefined. Null means that the variable has been set to an object whose value is undefined. Undefined means that the variable has no value or object assigned to it. 3. User-defined data types: – the data types which are declared by the user like enums, classes, arrays, etc. One of the types is also referred to as Type Alias
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TypeScript interface refers to the syntax that a system needs to follow. It is a virtual structure that exists within the context of typescript. It is mainly used for type checking purposes. It is simply a structural contract that defines the properties of an object is having like name and its type. An interface also defines the methods and events. It contains the only declaration of the members. Interface members should be declared by the derived class.
Head to Head Differences Between TypeScript Type and Interface (Infographics)
Below is the top 6 differences between TypeScript Type and Interface:
Key Differences between TypeScript Type and Interface
Below are the lists of points, describe the key differences between TypeScript Type and Interface:
- TypeScript Type declaration can introduce a name for any kind of type including primitive, union or intersection type. Interface declaration always introduced the named object type.
- The syntax for Type can be written as ‘type ABC = {a: number; b: number;}’. The syntax for interface can be written as ‘interface ABC = {a: number; b: number;}’.
- In TypeScript, type does not create a new name for instance. In TypeScript, an interface can create the new name that can be used everywhere.
- Type does not have a functionality of extending. An interface can extend multiple interfaces and class as well.
- Type is mainly used when a union or tuple type needs to be used. In typescript, sometimes developers cannot express some of the shapes with an interface.
TypeScript Type and Interface Comparison Table
Below is the topmost comparison between TypeScript Type and Interface.
| Basis Of Comparison Between TypeScript Type vs Interface | TypeScript Type | TypeScript Interface |
| Definition | It allows the creation of the new name for a type. | An interface provides the powerful way to define entities. |
| Capabilities | In TypeScript, Types are with fewer capabilities comparatively. | In TypeScript, Interface provides us with more capabilities. |
| Declarations | Type cannot have multiple merged declarations. | An interface can have multiple merged declarations. |
| Extend | Type for an object cannot be used. | An interface can be used in conjunction with other keywords. |
| Identical Name | In TypeScript, if two types are having identical names it will throw an exception. | In TypeScript, if two interfaces are having identical names it will get merged. |
| Implemented | Type cannot be implemented, it can be declared only. | Interface members are getting implemented by the derived class. |
Conclusion
TypeScript type vs interface are the important concepts of Typescript. Type Aliases are sometimes similar to interfaces. Type Alias a primitive is not terribly useful, though it can be used for documentation. It can be generic like interfaces, where we can just add parameters and use them on the right side of a declaration.
An interface has a feature of optional properties. These interfaces can be written similar to other interfaces. The optional property can be denoted with the symbol ‘?’ at the end of the name of the property while declaring it. The advantage of using this property is these can be available properties. It also prevents the use of properties which are not part of an interface. It has other features like use of read-only properties, excess property checks, function types, index types, class types and hybrid types
Typescript is popular nowadays among the Angular developers and it is being widely used for developing the applications. The above is the difference explained between the typescript type vs interface that helps you to know about their basic things. Each of them having its own usage to work over the other.
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