Could somebody please explain what this notation is in javascript? What is function(d) doing? In this program it seemse that x is called by the following, but I have no idea what any of this means. Thanks in advance...
x = function(d) { return d.x * width / mx; };
// later....
x({x: .9}); // call
.9 is a value of the property x of the object(d) being passed into the function.
In the function, d = {x:9}(object) , now when you ask for d's property(x) Value (using DOT notation), it returns the value for the property x.
so d.x returns 0.9!
So you would ask me how did i pass the value of the property into the function-X in the first place, well thats what we did when we dis this -> x(objectBeingSent); where objectBeingSent is {x: .9}.
Anonymous functions are functions that are dynamically declared at runtime. They’re called anonymous functions because they aren’t given a name in the same way as normal functions.
Anonymous functions are declared using the function operator. You can use the function operator to create a new function wherever it’s valid to put an expression. For example you could declare a new function as a parameter to a function call or to assign a property of another object.
The function operator returns a reference to the function that was just created. The function can then be assigned to a variable, passed as a parameter or returned from another function. This is possible because functions are first class objects in javascript.
Here’s an example where a function is declared in the regular way using the function statement:
function eatCake(){
alert("So delicious and moist");
}
eatCake();
Here’s an example where the same function is declared dynamically using the function operator:
var eatCakeAnon = function(){
alert("So delicious and moist");
};
eatCakeAnon();
See the semicolon after the second function's closing bracket? }; You use a semi-colon after a statement. This is a statement:
var eatCakeAnon = function(){
alert("So delicious and moist");
};
P.S. Best explanantion that i could find!
.9 is NOT a property of any object. It is a number literal that is the same as 0.9. .9 is the value of property x of the object.It's called an anonymous function. The function takes an object in the form of {x: number} as an argument and does some math on number.
). For the function syntax, have a look at MDN: developer.mozilla.org/en/JavaScript/Reference/Operators/….