Veryyyy long "if else" statement don't you think? Try to break down your array into 4 small ones. Then we can use them to compare if the inbound answer is inside one of the arrays. Also, this function doesn't correlate with your array at all.

Wow! Maksim - this is so useful. Thank you for taking the time to review! I'm also very impressed that you fixed the bug in your version. I made a few corrections based on your advice. Hope I understood your feedback correctly.

We also can set our array outside of the function, for better readability.

Hi Malkit, You doing great even you cover the extra one. in calculateSalesTax function return you multiply preTax with 1.2. I think it should be 0.2.

I believe in this case the multiplying by 1.2 is correct as the script is expecting it to return the value with sales tax added, however the name of the function doesn't make this clear. Maybe it would be better if the function was named calculateAndAddSalesTax(preTax)

I agree Michael then name of the function could be more meaningful.

Suggestion: use the let keyword to declare the variable

e.g. let total = a + b

The code will work without it but using let scopes the variable to the getTotal function. Without let is there was another function that used a variable called total you could see conflicts.

Thought: This is correct, but it's worth noting that the number may not be an integer, and could be 0 but cannot be 10.
See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/random for more info

Nitpick: you've described what the concat method does, but not what the combine2Words function does. A better description would be

combine2words returns a string of word1 and word2 joined together

Nitpick: This is fine, but reads a little funny to me. you could also do something like this
return `${firstWord} ${secondWord} ${thirdWord}`

I believe in this case the multiplying by 1.2 is correct as the script is expecting it to return the value with sales tax added, however the name of the function doesn't make this clear. Maybe it would be better if the function was named calculateAndAddSalesTax(preTax)

Suggestion: Avoid using the toFixed for math operations, as toFixed converts the number to a string. For a pure math function it is better to use the Math.round(val) function to avoid the conversion to a string.

Suggestion: While you've correctly broken down the code into appropriate lines, it would be better to use meaningful variable names rather than goodCode

Thanks Michael, I changed the names of the intermediate values, but kept the last variable name as goodCode as it is used in the actual test.

Suggestion: Repeating the options from the 4 arrays below in one large predictions array will be difficult to maintain for future changes instead you can create the predictions array after you've defined the other 4.
let allAnswers = [...vposArr , ...posArr , ...negArr , ...vnegArr];

Issue: I think adding the +1 here is incorrect and could give an 'index out of bounds' error if the Math.floor(Math.random() * 20) returns 19. This is because JavaScript arrays are zero indexed meaning in an array of 20 items the first index is 0 and the last is 19. By adding one you are changing the range of values instead from 1 to 20.
Suggestion: Don't hard code the number 20, if someone removes an item from predictions without updating this it will break. Instead use predictions.length