Glossary of JavaScript Tutorial Concepts

Syntax

The proper spelling, arrangement, and punctuation of keywords in a language.

Semantics

The meaning of a text with valid syntax. In a programming language, the result is some returned data or action, which may or may not be what was intended.

Language

A mapping between Syntax and Semantics.

Dictionary

A list of keyword or variable definitions, which can be quickly accessed by entering the keyword or variable name.

Keywords

The words provided in the initial dictionary of the JavaScript language.

Statement

A complete sequence of valid syntax with actionable semantics. Like a sentence, but ending with a ";" instead of a "." for some weird reason.

Program

1. Code that implements some functionality via a sequence of statements.
2. A dictionary of definitions of functions and data structures.

Scope

A set of statements in which a specific variable is known and accessible. In different scopes, different variables may be known or unknown. Even variables with the same name may have different values depending on the scople. A variable defined outside a block, and one of the same name defined inside the scope, can have different values without interfeering with each other. In that case, any reference to the variable name inside the block, can only reach the variable defined in the block; any reference to the name outside the block, can only reach the variable defined outside the block.

Block

Collection of statements which act together and enclose a block scope. Indicated by surrounding the statements with curly brackets. {} Blocks are the syntax for achieving scope.

Variables

Labels for boxes in memory which can hold anything. These are also new entries in the dictionary which you define.

Objects

Variables which are more complex and can hold other variables, and generally know how to do things to themselves. Basically everything in JavaScript is an object, although some can't be changed / varied.

Attribute

Variable inside an object

Functions

Objects which contain statements which cause the computer execute their instructions. They can be executed by following them with opening and closing parentheses, which can contain arguments. This is referred to as "calling" the function. They are defined by the function keyword, followed by a block of statements. They can be unnamed, or a name can be specified by assignment (let name = function(){}) or by placing the name between "function" and the parameter list (function name () {}).

Method

Functions in objects. A method is an attribute of an object with a value which contains the result of defining a function.

Parameters

Variables in the definition of a function which are replaced by arguments when the function is called. This lets us use the same function to act on different variables.

Arguments

Values or variables specified when we call a function. The arguments used in the call to the function set the values of the parameters in the definition of the function. Normally, arguments are listed inside parenthesis () after the function name when we call it. func_name(arguments)

Operators

+, -, *, /, stuff like that. Operators are just functions with very short weird names that take arguments from either side

Values

Raw data, like numbers and strings of characters (which are just numbers in ASCII (everything in a computer is a number))

Encapsulation

Putting boxes inside other boxes.

Information Hiding

Making the inner boxes invisible so they don't clutter up the view

Abstraction

Applying a general idea (layout or Method) over many specific Instantiations. See "this"

Instantiation

Copying the layout of a box and filling the spaces with new data

Inheritance

Re-using the layout of one box and extending it into a more complex layout

Mutable

Able to change

Constructor

Function that initializes a new object