Full stack Development $$ I

Instructions for a lab test submission involving JavaScript $($ES$6)$ and Node.js$.$

Here$$s a quick checklist and guide for completing your lab test and submission:

Developer Note:

When working on your questions, please create separate folder for your

work. This way you won$$t be putting all your code in the same file, which can

pollute the global namespace. In short, it will prevent you from overwriting your

own work and causing your code to compile incorrectly.

Organize your folder structure in this way $($Use it as a reference$)$

$1.$ Folder Structure and Code Organization

$$ Create a folder for your work to ensure you don$$t pollute the global

namespace.

o Example: studentid$\_$comp$3123\_$labtest$1/$

$$ Create separate files$/$modules inside the folder if needed to avoid

overwriting code.

$2.$ Documentation Resources

$$ JavaScript ES$6$ Documentation: MDN JavaScript Docs

$$ Node.js Documentation: Node.js Docs

Question $1$: ES$6$ Features

$$ Create a script with a function named lowerCaseWords that takes a

mixed array as input.

The function will do the following.

o return a promise that is resolved or rejected

o filter the non$-$strings and lower case the remaining words

$$ Input

const mixedArray $=[\text{'}$PIZZA$\text{'},10,$ true, $25,$ false, 'wings'$]$

$$ Output

Output $[$ 'pizza', 'wings'$]$

Question $2$: Promises

$$ Given the script file callbacks.js$,$ write a script that does the following:

o Create a method resolvedPromise that is similar to

delayedSuccess and resolves a message after a timeout of $500$ms$.$

o Create a method rejectedPromise that is similar to

delayedException and rejects an error message after a timeout of

$500$ms$.$

o Call both promises separately and handle the resolved and reject

results and then output to the console

callbacks.js

const delayedSuccess $=()=>\{$

setTimeout$(()=>\{$

let success $=\{$ 'message': 'delayed success!$\text{'}\}$;

console.log$($success$)$;

$\},500)$;

$\}$;

const delayedException $=()=>\{$

setTimeout$(()=>\{$

try $\{$

throw new Error$(\text{'}$error: delayed exception!$\text{'})$;

$\}$ catch $($e$)\{$

console.error$($e$)$;

$\}$

$\},500)$;

$\}$;

delayedSuccess$()$;

delayedException$()$;

$$ Output

$\{$ message: 'delayed success!$\text{'}\}$

$\{$ error: 'delayed exception!$\text{'}\}$

Question $3$: File Module

$$ Create a script that will do the following:

$1.$ Remove Log files

o remove all the files from the Logs directory, if exists

o output the file names to delete

o remove the Logs directory

$2.$ Create Log files

o create a Logs directory, if it does not exist

o change the current process to the new Logs directory

o create $10$ log files and write some text into the file

o output the files names to console

o Hint: use the fs module and path module, and the process current

working directory to build directory path. It is acceptable, to have a

remove.js script and separate add.js script.

$>$ Output

loge$.$txt log$1.$txt log$2.$txt log$3.$txt log$4.$txt log$5.$txt log$6.$txt log$7.$txt log$8.$txt log$9.$txt

delete files...loge$.$ txt delete files...log$1.$txt delete files...log$2.$txt delete files...log$3.$txt delete files...log$4.$ txt delete files...log$5.$ txt delete files...log$6.$txt delete files $...$log$7.$txt delete files...log$8.$txt delete files $...$log$9.$txt