Instruction: Provide an explanation of the Declaration Merging concept with examples of its practical applications.
Context: Aims to evaluate the candidate's understanding of TypeScript's unique feature, Declaration Merging, and its ability to merge two or more separate declarations into a single definition.
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For instance, consider the scenario where you're working on a large-scale application as a Frontend Developer. Here, interfaces become incredibly useful for defining the shape of data across the application. Sometimes, you might define an interface in one part of the application and realize later on that you need to extend or add more properties to it in another module or component. Instead of refactoring the original interface or creating a new one, TypeScript's Declaration Merging allows you to simply declare the same interface name with the new properties, and TypeScript will automatically merge these into a single interface.
```typescript interface User { name: string; }...