Gain insights into TypeScript's core concepts, from basics to advanced type checking and iterators. Learn about static typing and JS library support through practical, hands-on experience.

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If you’re looking to move beyond vanilla JavaScript and take your skills to the next level, then you’ve come to the right place. TypeScript is an in-demand language that sits on top of JavaScript. This means you can do everything you can in JavaScript with TypeScript, but also enjoy countless other perks including support for JS libraries, NPM, static typing, and much more.

In this course, you’ll start from the beginning and work your way up to more advanced concepts like type checking, iterators, and manipulating objects and arrays. You'll get a chance to get your hands dirty with plenty of real practice along the way.

For JavaScript developers, TypeScript is a must-know language, not only for today but also for years to come. Don't miss out.

Learn TypeScript: The Complete Course for Beginners

# The `Partial` mapped type and setting properties to _optional_

TypeScript has a few mapped types that you can explore by looking in *lib.d.t.s*. The lib definition file comes in different flavors depending on the TypeScript version installed.

The `Partial` mapped type sets every property to optional. Instead of having one interface with all but one of the types required, only one type is needed. The creation of the real type, even with a mix of optional and read-only has to be built. Only in the scenario where information can be partially assigned to an object is it correct to have optional members.



Without mapped type, the duplication of a second interface is needed with all the same type functions and properties, but with a question mark to specify that `undefined` can be set (or that value can be forgotten). Nevertheless, it eases maintainability to always synchronize both interfaces. The solution is to use the built-in mapped type `partial`.

This lesson explains the partial mapped type.

Introduction

The Basics of Variables

Comment

Enum

Generic Type

Functions

Mapped Type

Objects

Index Signature

Variables Advanced

Exception

Alias

Type Checking

Iterators

Manipulating Objects and Array

Sharing Code

Conclusion

Partial

The `Partial` mapped type and setting properties to optional #

Partial

The Partial mapped type and setting properties to optional #

The `Partial` mapped type and setting properties to optional #