Add interface on this of the function-CodePudding

I am trying to add the type on this of the function but I am not sure how I can do it

interface ThisFunction{
    test:Function
}
function exampleFunction(){
//I want to add type of this to be of interface of ThisFunction like 
//I know that I will always bind the Test instance this should have interface as ThisFunction 
this.test();
}
//When I call the function
exampleFunction().bind({test: ()=>null})

CodePudding user response：

You can type this like that:

interface ThisFunction {
  test: Function
}

function exampleFunction(this: ThisFunction) {
  this.test();
}

const boundExampleFunction = exampleFunction.bind({ test: () => null })

boundExampleFunction()

This code is safe because TypeScript statically checks that this matches its declared type. For example it will throw an error if you try to call exampleFunction without binding it. However, you could inline the function declaration and the bind operation if you don't want to expose the unbound function as a variable:

interface ThisFunction {
  test: Function
}

const exampleFunction = (function (this: ThisFunction) {
  this.test();
}).bind({ test: () => null })

exampleFunction();

CodePudding user response：

To type this, I think you could code it like that:

interface ThisFunction{
    test: Function
}
function exampleFunction(){
     const thing: ThisFunction = this
}