reading-notes

Readings: Debugging

Reading

What Went Wrong? Troubleshooting JavaScript

Name some key differences between a Syntax Error and a Logic Error.

• Syntax Error: These are spelling errors in your code that actually cause the program not to run at all, or stop working part way through — you will usually be provided with some error messages too. These are usually okay to fix, as long as you are familiar with the right tools and know what the error messages mean!
• Logic Error: These are errors where the syntax is actually correct but the code is not what you intended it to be, meaning that program runs successfully but gives incorrect results. These are often harder to fix than syntax errors, as there usually isn’t an error message to direct you to the source of the error.

List a few types of errors that you have encountered in past lab assignments and explain how you were able to correct them.

• I didn’t really understand the inpsect and console logging until this last lab. Even then I didn’t really understand what was broken and why. I am a tinkerer so I just kind of make little changes until my code works. Then I generally don’t make the same mistake again. Or at least not in the same way.

How will this topic continue to influence your long term goals?

• No matter how awesome one gets at coding you are still going to run across situations wherein you will need to trouble shoot. Realizing that I haven’t been tracking my problem solving has motivated me to keep a journal of issues and fixes

The JavaScript Debugger

How would you describe the JavaScript Debugger tool and how it works to someone just starting out in software development?

• an interactive tool that lets you live review code and check for processing errors in real time.

Define what a breakpoint is.

• points in the sourcecode where you want to pause execution

What is the call stack?

• shows you what code was executed to get to the current line.

Debugging Code in Repl

• debugging strategies
  • read error messages
    • line where the error happened
    • information about the error
  • checking variable names
    • confirming things match
  • syntax highlighting

‘use strict’;

// Welcome to my student generator app! There are currently 3 types of errors in this application, 1. TypeError, 2. SyntaxError, 3. ReferenceError. Use the errors in the console to pinpoint the specific line number where the issue occurs and fix each new error as they occur.

// TODO: Render our new student objects as a list in the console

var cache = [];

var students = ‘Robb,Chuck,Kendrah,Cesar,Zach,Rae,Jallow,Kevin,Micahel,Josh,Shane,JT’;

// constructor for each instance of a student object function Student(name) { this.studentName = name; this.emailAddress = null; this.registeredCourse = null; this.enrolled = false;

cache.push(this); }

function normalizeInput(str) { // simulate receiving CSV data from a file and normalize it for our constructor. expected output is an array of names that is ready to use later. var students = str.split(‘,’); for (var i = 0; i < students.length; i++) { students[i] = students[i].toLowerCase(); } return students; }

Student.prototype.validate = function() { return ${this.studentName} added to the cache; }

function studentGenerator(arr){ // given an array, populate our global cache with objects and store them in our global cache.

// check if array exists if(Array.isArray(arr)) { for(var i = 0; i < arr.length; i++){ var newStudent = new Student(arr[i]);
console.log(newStudent.validate());

}
return `Completed.  ${i} entries added to cache.`;   }   else {
return 'This function only accepts arrays.  please try again.'   } }

function initialize(input) { var studentList = normalizeInput(input);

return studentGenerator(studentList);
}

initialize(students);