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1What are interfaces in TypeScript?
2How to reopen Interface?
3Explain the difference between 'interface' and 'type' in TypeScript.
4How do we extend interfaces?
5Can we add new fields to interface and type?
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02 / 05

How to reopen Interface?

"Reopening the interface" in TypeScript refers to the ability to declare an interface with the same name multiple times, with TypeScript automatically merging all declarations into a single, combined interface. This feature is formally known as declaration merging.

  1. 1

    To reopen an interface, declare a new interface with the same name as the existing interface and add the new properties.

  2. 2

    The TypeScript compiler will merge the two interfaces, resulting in a single interface with all of the properties from both declarations.

For example, the following code shows how to reopen an interface to add a new property:
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