TypeScript Object with Dynamic Keys
October 26, 2023
When working with TypeScript, there might be scenarios where you do not have predetermined keys for an object. These dynamic keys can come from user input, external data, or other runtime sources. In this guide, we will explore different ways to define, create, and work with objects having dynamic keys in TypeScript.
For objects with dynamic keys, TypeScript provides the
Record type and index signatures.
You can use an index signature to specify that an object could have any number of properties of a certain type.
In this example, the keys are strings, and the values are also strings. You can change the value type as per your requirements.
Record type allows you to create an object type where you specify the key type and value type.
Using Enums as Keys
If you have a limited set of dynamic keys,
enums can be a handy choice.
Combining Static and Dynamic Keys
In real-world scenarios, you might have objects with both static and dynamic keys.
Nested Dynamic Keys
Objects can have nested structures with dynamic keys at various levels.
Constrained Dynamic Keys
At times, you'd want to constrain the dynamic keys to a specific set of values, perhaps based on another array or tuple.
obj can only have keys 'a', 'b', or 'c'.
Handling Unknown Keys
Sometimes, you might be unsure about the object's shape. TypeScript provides an
unknown type for such cases.
unknown forces you to type-check values before operating on them, enhancing type safety.
Using with Functions
When dealing with functions that operate on objects with dynamic keys, you can utilize generics for better type inference.
Remember, while dynamic keys provide flexibility, they can also introduce challenges in ensuring type safety. Always strive for the right balance between flexibility and safety when modeling your types.
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