How to infer an object type. | TypeScript Community | Page 1

Hello everyone,

I am playing around with typescript and I am stuck on how to infer the type of an object, here is what my code looks like:

class Responnse<Context = null> {
  private context: Context | null = null;

  constructor(props?: { createContext?: () => Context }) {
    if (props && props.createContext) {
      this.context = props.createContext();
    }
  }

  public middleware = (
    cb: ({
      context,
    }: {
      context: //What type should go there ?, so that context from the consumer is infered
      Context;
    }) => void,
  ) => {
         // getting a ts error over here see the ts playground for more context.
    cb({ context: this.context });

    return this;
  };
}

The consumer code:

const updateWhatever = () =>
  new Responnse({
    //optional createContext function. if createContext function is not there, then the context should be infered as null,
    // if its there then context should be the return type of this function
    createContext: () => {
      return {
        name: "micheal?",
      };
    },
  })
    .middleware(({ context }) => {
      //the context object here should be infered as {name:string} because the createContext return {name:'micheal'}
      console.log("start");
    })

If you need anything else please let me know.

#How to infer an object type.