这是命名约定还是函数声明

Question

I am learning javascript and now started with objects and basic functions. I came across this type of code and was wondering what exactly is this

var stringFunction = function(){};

stringFunction.test1 = function(){
  console.log("Test 1");
}

does test1 is a part of stringFunction or just a naming convention.Thanks in advance

Answer 1

function instances are sort of "weird" in Javascript as they are objects but their typeof is "function" and not "object" .

They can however have properties added and accessed using either the syntax fx or f["x"] . Your code simply adds a property to a function object (the value of the property is also a function, but that is irrelevant).

Answer 2

Here test1() is a property (function type) of the stringFunction var.
So you defined a function in a function object.

You can use it by invoking stringFunction.test1(); as you can invoke the outer function : stringFunction();

var stringFunction = function(){console.log("Test stringFunction")};

stringFunction.test1 = function(){
    console.log("Test 1");
}

stringFunction();
stringFunction.test1();

OUTPUT :

Test stringFunction

Test 1

Answer 3

in JavaScript every function is a Function Object. see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function . In you sample the code create a property 'test1' on object stringFunction. The new property is itsealf a Function Object.