- Introduction
- Chapter 1 Values, Types, and Operators
- Chapter 2 Program Structure
- Expressions and statements
- Variables
- Keywords and reserved words
- The environment
- Functions
- The console.log function
- Return values
- prompt and confirm
- Control flow
- Conditional execution
- while and do loops
- Indenting Code
- for loops
- Breaking Out of a Loop
- Updating variables succinctly
- Dispatching on a value with switch
- Capitalization
- Comments
- Summary
- Exercises
- Chapter 3 Functions
- Chapter 4 Data Structures: Objects and Arrays
- Chapter 5 Higher-Order Functions
- Chapter 6 The Secret Life of Objects
- Chapter 7 Project: Electronic Life
- Chapter 8 Bugs and Error Handling
- Chapter 9 Regular Expressions
- Creating a regular expression
- Testing for matches
- Matching a set of characters
- Repeating parts of a pattern
- Grouping subexpressions
- Matches and groups
- The date type
- Word and string boundaries
- Choice patterns
- The mechanics of matching
- Backtracking
- The replace method
- Greed
- Dynamically creating RegExp objects
- The search method
- The lastIndex property
- Parsing an INI file
- International characters
- Summary
- Exercises
- Chapter 10 Modules
- Chapter 11 Project: A Programming Language
- Chapter 12 JavaScript and the Browser
- Chapter 13 The Document Object Model
- Chapter 14 Handling Events
- Chapter 15 Project: A Platform Game
- Chapter 16 Drawing on Canvas
- Chapter 17 HTTP
- Chapter 18 Forms and Form Fields
- Chapter 19 Project: A Paint Program
- Chapter 20 Node.js
- Chapter 21 Project: Skill-Sharing Website
- Eloquent JavaScript
- Exercise Hints
- Program Structure
- Functions
- Data Structures: Objects and Arrays
- Higher-Order Functions
- The Secret Life of Objects
- Project: Electronic Life
- Bugs and Error Handling
- Regular Expressions
- Modules
- Project: A Programming Language
- The Document Object Model
- Handling Events
- Project: A Platform Game
- Drawing on Canvas
- HTTP
- Forms and Form Fields
- Project: A Paint Program
- Node.js
- Project: Skill-Sharing Website
Abstraction
In the context of programming, these kinds of vocabularies are usually called abstractions. Abstractions hide details and give us the ability to talk about problems at a higher (or more abstract) level.
As an analogy, compare these two recipes for pea soup:
Put 1 cup of dried peas per person into a container. Add water until the peas are well covered. Leave the peas in water for at least 12 hours. Take the peas out of the water and put them in a cooking pan. Add 4 cups of water per person. Cover the pan and keep the peas simmering for two hours. Take half an onion per person. Cut it into pieces with a knife. Add it to the peas. Take a stalk of celery per person. Cut it into pieces with a knife. Add it to the peas. Take a carrot per person. Cut it into pieces. With a knife! Add it to the peas. Cook for 10 more minutes.
And the second recipe:
Per person: 1 cup dried split peas, half a chopped onion, a stalk of celery, and a carrot.
Soak peas for 12 hours. Simmer for 2 hours in 4 cups of water (per person). Chop and add vegetables. Cook for 10 more minutes.
The second is shorter and easier to interpret. But you do need to understand a few more cooking-related words—soak, simmer, chop, and, I guess, vegetable.
When programming, we can’t rely on all the words we need to be waiting for us in the dictionary. Thus, you might fall into the pattern of the first recipe—work out the precise steps the computer has to perform, one by one, blind to the higher-level concepts that they express.
It has to become second nature, for a programmer, to notice when a concept is begging to be abstracted into a new word.
This is a book about getting computers to do what you want them to do. Computers are about as common as screwdrivers today, but they contain a lot more hidden complexity and thus are harder to operate and understand. To many, they remain alien, slightly threatening things.
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