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As I learn JavaScript I've been looking around the web and seen numerous references to constructs in Javascript, but I can't seem to find a complete definition of what they are and what they are not, especially in the context of Javascript.
For instance, in 'Similar Questions' I see links that lead to an example featuring the following code:
In What is this construct in javascript?:
(function () {
})();
From what I understand this is a construct, but what are they defined by?
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In JavaScript, the thing called this is the object that "owns" the code. The value of this, when used in an object, is the object itself. In a constructor function this does not have a value.
In the above example, function Person () is an object constructor function. To create an object from a constructor function, we use the new keyword. Note: It is considered a good practice to capitalize the first letter of your constructor function.
The constructor () method is called automatically when a class is initiated, and it has to have the exact name "constructor", in fact, if you do not have a constructor method, JavaScript will add an invisible and empty constructor method. Note: A class cannot have more than one constructor () method. This will throw a SyntaxError.
User-defined Constructors These are the constructors declared and defined by the programmer to be used throughout the application. A programmer can also define properties and methods of their own custom types. They are also known as custom constructors. By convention, all JavaScript constructors are sentence-cased.
Construct is a generic term referring to an arbitrary aggregate of code in a specific formation. It is not a javascript-specific term.
Basically, it can apply to anything. So, while the code you referenced is a construct known as a self invoking anonymous function, var x = "hello world"; is a construct known as a variable declaration and assignment.
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A "language construct" is the full term you're looking for. According to the linked definition:
A language construct is a syntactically allowable part of a program that may be formed from one or more lexical tokens in accordance with the rules of a programming language.
So it's any valid segment of written code that follows the rules of the language. It's a generalisation of words like "expression", "statement", "function argument list", "assignment statement", "keyword", "function definition", etc. that each define a series of tokens to look for and what they will mean in the rules of the language. The code of a completed program is constructed with them.
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