Add Defaultable<T>

[waynemwashuma]

Objective

Adds a new interface which enforces a class to have a static method default() which is used to create a default object of the class.

Currently cannot be directly enforced on a class as explained in this issue.Will be enforced in functions/methods which accept classes.

This was inspired by the rust language Default trait.

Solution

N/A

Showcase

Javascript:

class Something {
  static default(){
    return new Something()
  }
}

/**
  * @template T
  * @param {Defaultable<T>} that
  * @returns T
  */
function createSomething(that){
  const a = Something.default()
  return a
}

const something = createSomething(Something)

Typescript:

class Something {
  // this is the method required by `Defaultable<T>`
  static default(){
    return new Something()
  }
}

function createSomething<T>(that:Defaultable<T>):T{
  const a = Something.default()
  return a
}

const something = createSomething(Something)

Migration guide

N/A

Checklist

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.