design software

programming

• programmers combine primitive elements to form compound objects, they abstract compound objects to form higher-level building blocks, and they preserve modularity by adopting appropriate large-scale views of system structure.

  • primitives -> compound objects -> higher-level blocks -> module -> system

• Metalinguistic abstraction — establishing new languages

  • Establishing new languages is a powerful strategy for controlling complexity in engineering design
  • enhance our ability to deal with a complex problem by adopting a new language that enables us to describe (and hence to think about) the problem in a different way, using primitives, means of combination, and means of abstraction that are particularly well suited to the problem at hand

JS

• Module design

  • ini package

• data structures

  • primitive values: num, booleans, strings

    • immutable and cannot be changed
    • copied "as a whole value"

  • arrays and objects are used to group values into a single value

    • arrays - sequence of values

    • objects - dict

      • reference - binding
      • mutable

    • object is stored and copied "by reference"

    • most objects also have a prototype

      • a prototype is another object that is used as a fallback source of properties
      • Object.prototype

• JS functions are regular values representing an "action"

  • higher-order functions allow us to abstract over actions, not just values
    • pass function values to other functions

• OOP

  • divide programs into smaller pieces and make each piece responsible for managing its own state

  • different pieces interact with each other through interfaces

    • pieces are modeled using objects
    • their interface consists of a specific set of methods and properities

  • encapsulation

    • separate interface from implementation

• class

  • in JS, a class is a kind of function
  • a class is an extensible program-code-template for creating objects, providing init values for state (variables) and implementations of behavior (functions)

reference

• [JavaScript The Good Parts]