Sometimes, we want to dynamically assign properties to an object in TypeScript.

In this article, we’ll look at how to dynamically assign properties to an object in TypeScript.

How to dynamically assign properties to an object in TypeScript?

To dynamically assign properties to an object in TypeScript, we can define an interface that lets us accept any properties.

For instance, we write

interface MyType {
  typesafeProp1? : number,
  requiredProp1: string,
  [key: string]: any
}

let obj: MyType;
obj = {
  requiredProp1: "foo"
};
obj = {} 
obj.typesafeProp1 = "bar" 

obj.prop = "value";
obj.prop2 = 88;

to define the MyType interface.

The interface stipulates that that the MyType object can have the typesafeProp1 property and it’s a string.

It’s also requires the requiredProp1 property.

Also, we can add properties with keys other than the typesafeProp1 and requiredProp1 with [key: string]: any.

Therefore, obj = {} will give us a compile time error.

And obj.typesafeProp1 = "bar" will also give us an error since 'bar' isn’t a number.

Conclusion

To dynamically assign properties to an object in TypeScript, we can define an interface that lets us accept any properties.