Also read: Callbacks
"It’s not that JavaScript didn’t execute our functions in the order we wanted it to, it’s instead that JavaScript didn’t wait for a response from first() before moving on to execute second()."
" you can’t just call one function after another and hope they execute in the right order."
"Callbacks are a way to make sure certain code doesn’t execute until other code has already finished execution."
- an invocation, in this context, of a function.
- one
- Last In, First Out
- which "means that the last function that gets pushed into the stack is the first to be pop out, when the function returns."
Draw an example of a call stack and the functions that would need to be invoked to generate that call stack.
A call stack is a to do list
the call stack is an ordered set of stack frames. It's a to-do list for function calls or invocations. The bottom of the stack is the first function invoked.
Imagine a stack of books. The first function is the book on the bottom of the pile, the next function invoked is second, etc.
The last function (or book) on the pile is the first one to be removed. If you tried to remove a bottom book, you would get jenga.
Exceeding the number of frames allowed in the call stack An infinite loop. Anything that runs to the point it fills up memory.
"This is as simple as when you try to use a variable that is not yet declared you get this type of errors."
"this occurs when you have something that cannot be parsed in terms of syntax"
"Try to manipulate an object with some kind of length and give it an invalid length and this kind of errors will show up."
"when the types (number, string and so on) you are trying to use or access are incompatible"
Placing a stop point in your code to see what is happening.
"when running the code you can see the “history” before reaching that breakpoint"
Learning to debug your code is a huge part of programming. Getting comfortable with it and learning to do it well is important.
"Being able to read error messages and practising debugging is one of your biggest weapons has a developer, do it frequently and with enough time you will notice a great decrease in the time you spend on each error that you find along the way."
More on Node.js Computers can not directly run JS or compile it down to Machine code.
We pass JS through v8 (a c++) to compile it.
Node.js is a program written in c++ that wraps around v8 (also written in c++) and is It takes JS, Runs it through the v8 compiler and compiles our JS into machine code. Reads and write files connect to a database Act as a server for content. It allows me to run JS on the front end and the backend, something I wouldn't be able to do without node..I would have to use a backend server language.