Function Patcher

Allows you to alter what functions do.

Usage

Example module, that includes functions we can patch.

const myModule = {
  myFunction() {
    console.log("[Original]: ran")
    return "myReturn"
  },
  myOtherFunction() {
    console.log("[Original]: ran")
    return "myOtherReturn"
  }
}

Basic

patcher.type(module, function, callback)

Before

Using the basic templat but for the type is Before. In the callback you get 2 arguments

• arguments is an array of the arguments passed to the function.
• this is the this value of the function. You dont need to return any values (will not be used at any point).

patcher.before(myModule, "myFunction", (args, thisItem) => {
  console.log("[Before]: ran")
})

Instead

Using the basic templat but for the type is instead. In the callback you get 3 arguments

• arguments is an array of the arguments passed to the function.
• original is the original value of the function. (or a instead function)
• this is the this value of the function. You need to return a function or nothing. (if nothing is returned the original function will be used)

patcher.instead(myModule, "myFunction", (args, original, thisItem) => {
  console.log("[Instead]: ran")
  // The returned function gives the result to 'after'
  return () => {
    const result = original.apply(thisItem, args)
    console.log("[Instead]: return function ran")
    return result
  }
})

After

Using the basic templat but for the type is after. In the callback you get 3 arguments

• arguments is an array of the arguments passed to the function.
• returnValue is the value returned by the function.
• this is the this value of the function. You dont need to return any values (will not be used at any point).

patcher.after(myModule, "myFunction", (args, result, thisItem) => {
  console.log("[After]: ran")
})

Undo

All patches return a undo value.

const undo = patcher.after(myModule, "myFunction", (args, result, thisItem) => {
  console.log("[After]: ran")
})
// Later on
undo()

Example

const myModule = {
  myFunction() {
    console.log("[Original]: ran")
    return "myReturn"
  },
  myOtherFunction() {
    console.log("[Original]: ran")
    return "myOtherReturn"
  }
}
const undo = patcher.before(myModule, "myFunction", (args, thisItem) => {
  console.log("[Before]: ran")
})
// this will log both logs
myModule.myFunction("myArgument")
// undo
undo()
// this will log only the original log
myModule.myFunction("myArgument")