The best authors and the best JavaScript developers are those who obsess about language, who explore and experiment with language every day and in doing so develop their own style, their own idioms, and their own expression.
Take your first steps into programming by learning to read, trace, analyze, and write interactive programs in your browser.
By the end of this module using Just Enough JavaScript you will be able to document, plan and develop programs that process a user's text input.
- Learning Objectives: what you can expect to learn from studying this material
- Setting Up: how to set up and study this material
- Suggested Study: Helpful links for this module, useful but not required.
- Lesson Plans: A few ideas for running lessons around this material.
- Study Tips: Some tips for getting the most out of your time learning to program.
all of these skills are limited to short, single-page programs written with Just Enough JavaScript
What is a program? What is a programming language? How do programs and people fit together?
- Data in, Data Out: You understand that computer programs are used to transform data, and can explain a JS program from this module in terms of the data that goes in and the data that comes out.
- Three Audiences: You can explain how a single file of code is used to communicate with 3 different audiences:
- Developers: You can explain how code formatting, comments, logs and variable names make it easier (or harder!) for a developer to understand a program.
- Computers: You can explain how a computer follows your instructions to store, read and modify data in program memory.
- Users: You can explain how the computer creates a dynamic user experience by following different executions paths depending on user input.
- Tracing Variables: You can complete a trace table for a program that uses only variables, and can check your work using the "trace" button.
Go in depth on JavaScript you need to know for writing interactive text-based programs in the browser. Along the way you will learn how each language feature works in small programs.
- JavaScript Syntax: Given a program, you can identify these parts of JavaScript syntax:
- Primitives
- Operators
- Identifiers
- Keywords
- Checks
- Blocks
- Function Calls
- Listening and Reading: You can read code out loud, and understand your classmates when they read code to you. You don't need to understand how a program works to master these learning objectives!
- Listening You can exactly re-write a program that a classmate has read
- Reading You can read a program out loud and guide your classmates to re-write exactly the same code without them seeing the program. Every indentation, semi-colon, comment and spelling in their program must be identical to yours.
- Static vs. Dynamic Analysis: You can explain and use these two ways of studying a program, each can help you understand different aspects of your code. To help understand this concept, the options panel in Study Lenses is organized into static and dynamic study options:
- Static: Studying the text in a code file without running it. Some static study methods are creating a flowchart, analyzing variables, filling out a trace table, and drawing on code.
- Dynamic: Running code and studying the computer's behavior. Some dynamic study methods are running code and reading console logs, using the trace button, and stepping through in the debugger or JS Tutor.
- Tracing Execution: You can complete a "steps" trace table for all JS language features in Just Enough JavaScript, and can correct your table using console output from the "trace" button.
- Analyzing Variables: You can list all the variables in a program, and
answer these 5 questions for each variable:
- Where is the variable declared?
- What is the variable's scope?
- Is the variable initialized with a value?
- How many times is its value used (read) in the program?
- How many times is the variable assigned a new value?
- What types are assigned to this variable during the program's execution?
- Completing Programs: You can successfully fill in blanks for a program when the missing words are provided, including distractors.
- Translating Pseudo Code: Given a program written in Pseudo Code, you can translate it to working JavaScript.
- Comparing Programs: You can compare two programs with similar code and explain if they have the same behavior or not. If they do not, you can explain how they behave differently and why.
- Constructing Programs: You can reconstruct a program's lines and indentation, successfully ignoring distractor lines.
Learn how to understand a larger programs by finding connections between the details and the big picture. By the end of this chapter you will know how to read a new program and do a simple code review.
- Stepping Through: You can pause a script in a your browser's debugger, arrange the debugger, collapse extra panels, and step through a script written with Just Enough JS. At each point in execution you can make a prediction of the next line before executing, and can check your prediction using the scopes panel.
- Imperative Programming: You can explain what the Imperative Programming paradigm is, and can explain how you know the programs in Welcome to JS are Imperative.
- Program Goals: You understand that a full JavaScript program can be explained as a series of smaller goals, and can write names for the goals in a simple working program.
- Logging: You can tracing specific aspects of a program's execution and log them to the console.
- Tracing Backwards You can trace backwards from a program's output to it's input.
- Naming Variables: You can analyze how a variable is used in a program
and give it two names:
- Generic: You can give a generic name to a variable based on how it is used in the program.
- Specific: You can give a specific name to a variable based on how it's used and the program's domain (the program's specific data and use-case).
- Describing Programs: You can read a program and describe it with
comments using to the methodology from
/describing-programs:- Zoom Out
- Zoom In
- Find Connections
- Describe Goals
- Code Review: Given a working program you can review the code for clarity, correctness and style.
- Same Behavior, Different Code: You can study simple programs with the same behavior (data in, data out) but different source code and explain how the differences matter for each audience.
Learn to modify and write larger programs in JavaScript. You'll cover many of the hidden skills necessary to develop quality software and to work collaboratively on a code base.
- Linting: You can find and fix simple linting errors in JavaScript programs.
- Program Life Cycle: You can explain the two phases of a program's life
cycle.
- Creation Phase
- Execution Phase
- Fixing Errors: You can use the structured comment to describe an error in your program, and can make several educated guesses at how to fix the error.
- Fixing Bugs: You can use the structured comment to describe and fix a bug in small programs.
- Modifying Programs: You can make small changes in a program to change its behavior without breaking it.
- Refactoring: Given a working program, you can make changes to the code without changing the program's behavior.
- Writing Programs: Given a description of a program's behavior (user story + test cases), you can plan goals for the program and write code to pass the tests.
- Reverse Engineering: Given a working program with unreadable code, you can:
- Give the program a name.
- Describe the program's behavior with a user story, acceptance criteria and test cases.
- Plan goals for the program.
- Develop your own working program with the exact same behavior.
- Imagining Programs: Given an empty page, you can imagine and develop your own programs using Just Enough JavaScript. This includes:
- A title.
- A description with a user story, acceptance criteria and test cases.
- Commented goals.
- Fully working Code.
expand/collapse
You will need
- clone or fork the repo
https://github.com/HackYourFutureBelgium/bf-welcome-to-js.git. - cd
bf-welcome-to-js npm installstudy- if you want to close
studyusectrl + c
This repository comes with some scripts to check the quality of this code. You can run these scripts to check the code provided by HYF, and to check the code you write when experiment with the examples and complete the exercises.
This script will format all of the code in this repository making sure that all the indentations are correct, the code is easy to read, and letting you know if there are any syntax errors.
This script will check all of the files in your repository for spelling mistakes. Spelling is not just a detail, is important! Good spelling helps others read and understand your programs with less effort.
spell-check is not so clever though, it doesn't have all possible words in
it's dictionary and it won't know if you wanted to spell a word incorrectly.
If you think one of it's "Unknown word"s is not a problem, you can either ignore
the suggestion or add the word to the "words": [ ... ], list in
.cspell.json.
This script will lint all the Markdown files in this repository, checking for syntax mistakes and other bad practices. Fixing linting errors will help you learn to write better code by pointing out your mistakes before they cause problems in your program.
Some linting errors will take some practice to understand and fix, but it will be a good use of time.
Just like lint:md, but for .js files. This script will lint all of the JS
files in this repository, letting you know if there are any syntax errors or bad
practices.
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