JavaScript syntax
part 50/59 · 107.4 KB total
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────
const myStructure = {
name: {
first: "Mel",
last: "Smith"
},
age: 33,
hobbies: ["chess", "jogging"]
};
This is the basis for JSON, which is a simple notation that uses JavaScript-like syntax for data exchange.
Methods
A method is simply a function that has been assigned to a property name of an object. Unlike many object-oriented languages, there is no distinction between a function definition and a method definition in object-related JavaScript. Rather, the distinction occurs during function calling; a function can be called as a method.
When called as a method, the standard local variable this is just automatically set to the object instance to the left of the ".". (There are also call and apply methods that can set this explicitly—some packages such as jQuery do unusual things with this.)
In the example below, Foo is being used as a constructor. There is nothing special about a constructor - it is just a plain function that initializes an object. When used with the new keyword, as is the norm, this is set to a newly created blank object.
Note that in the example below, Foo is simply assigning values to slots, some of which are functions. Thus it can assign different functions to different instances. There is no prototyping in this example.
function px() { return this.prefix + "X"; }
function Foo(yz) {
this.prefix = "a-";
if (yz > 0) {
this.pyz = function() { return this.prefix + "Y"; };
} else {
──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────