No index signature with a parameter of type ‘string’ was found

No index signature with parameter of type ” was not found is an error in typescript. The error basically comes when you try to access a value from object using a dynamic key.

No index signature with a parameter of type ‘string’ was found

How to solve No Index Signature error

The solution of this problem is to use as keyof on the field you are using as a key.

Let’s understand it by taking an example code. I have a model UserModel with three fields – userName, customerName and userId

So instead of using this.key directly, you need to use this.key as keyof UserModel which will solve the Error. It says that the key field you are providing, is a key of model itself. So after that it won’t complain about No Index Signature with parameter of type ‘string’ was found.

No index signature with a parameter of type ” was found

The same error may occur when you do not use a Model Class in your data variable and try to access it with a dynamic key.

No index signature with a parameter of type ‘string’ was found on type ‘{ userName: string; customerName: string; userId: number; }’.

How to solve no index signature error in object

Create Interface (you can create Model Class as well) with the fields according to your Object. In my case I have three fields so I have created an interface like this-

Now declare the user object variable with the interface.

And finally use as keyof operator at the time of accessing the data.

Complete code-

Use Interface with keyof operator

Conclusion

As this article already covered how to solve “No index signature with a parameter of type ‘string’ was found”, what’s next ? I would say try to Integrate Internationalization (i18) in Angular.

Also Read: How to use Virtual Scrollbar in Angular Mat Select

3 thoughts on “No index signature with a parameter of type ‘string’ was found

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