从事一项任务，我只是不理解某些东西，但不确定我错过了什么（可能很多）

Question

Hey guys i'm working on an assignment and i am having difficulty but not sure what it is I am missing. it keeps throwing an error on Step 4

I am not really sure how to structure the code to satisfy the requirements for Step 4

and and all help is appreciated here.

Assignment Instructions In this exercise, you will work with some data provided as an array of objects, listing information about dishes available in the Little Lemon restaurant.

Step 1: In the function getPrices(), give it the parameter of taxBoolean.

Step 2: Inside the getPrices() function, code a for loop that will loop over all the objects inside the dishData array.

Step 3: Inside the for loop, declare a finalPrice variable, without assigning it a value.

Step 4: Still inside the for loop, add an if condition, checking that the taxBoolean is set to true. Inside the if block, multiply the following: * the price of the currently looped-over object from the dishData array, and * the tax value. Assign the multiplied value to the finalPrice variable.

Step 5: Right after the if condition, add an else if, checking if the value of taxBoolean is false. Inside this condition's block, assign the currently looped-over dish price property in the dishData array to the finalPrice variable.

Step 6: Code the else case, and inside of it, add two lines of code:

A console log of the string:

"You need to pass a boolean to the getPrices call!"

return (to "jump out" of the further function execution)

Step 7: After all the conditional's statements, but still inside the for loop, code another console log with four arguments:

The string "Dish: "

The value of currently looped-over dish object's name property

The string "Price: $"

The value of the finalPrice variable

Step 8: You're finshed with the getPrices() function, and now you're ready to code another function. Give the getDiscount() function, two parameters: the taxBoolean and the guests parameter.

Step 9: Inside the getDiscount() function, on the very first line of its body, invoke the getPrices() function, passing it the taxBoolean as an argument.

Step 10: On another line, you need to implement your defensive coding skills, and check that the type of the guests parameter is 'number' and that the value of the guests variable is greater than zero and less than 30. If all these conditions return true, code the body of the conditional as described in the next step. If they don't all return true, code the body of the else conditional as instructed in step 12.

Step 11: Inside the if statment, declare a new variable, named discount, and set it to 0. On the next line, add another if...else if: in the first if, you'll check that the value of the guests variable is less than 5. If that's the case, reassign the value of the discount variable to 5;

Inside the else if condition, check that the value of the guests variable is greater than or equal to 5 - if that's the case, reassign the discount variable to 10. Console log the following after closing your else-if statement: 'Discount is: $' + discount); Step 12: In the else condition, console log the following string: 'The second argument must be a number between 0 and 30'. Since you've finished declaring both the getPrices() and the getDiscount() functions, you can now invoke the getDiscount() function several times, with various combinations of arguments, to check the behavior.

Here are two examples:

getDiscount(true, 2) getDiscount(false, 10) What happens when you don't pass-in any arguments?

What happens when you pass values that are not expected?

// Given variables
const dishData = [
    {
        name: "Italian pasta",
        price: 9.55
    },
    {
        name: "Rice with veggies",
        price: 8.65
    },
    {
        name: "Chicken with potatoes",
        price: 15.55
    },
    {
        name: "Vegetarian Pizza",
        price: 6.45
    },
]
const tax = 1.20;

// Implement getPrices()

function getPrices(taxBoolean) {   //step1
    let finalPrice = "";
    for (var i = 0; i < dishData.length; i++) {   // step 2
         let finalPrice = 0                                           // step 3
        if (taxBoolean == true) {                  // step 4
            let name = dishData[i]['name'];
            let price = dishData[i]['price'];  // Step 4
            //console.log('Prices with 20% tax:');
            console.log(`Dish: ${name}, Price (incl. tax): $${+price * tax}`);
                  
        } else if (taxBoolean == false) {            //step 5
            let name = dishData[i]['name'];
            let price = dishData[i]['price'];
            console.log('Prices without tax:'); {
                console.log(`Dish: ${name}, Price (incl. tax): $${+price}`);
            }
        } else {                                        //step 6
            console.log("You need to pass a boolean to the getPrices call!")
            return;
        }
    }
}
console.log(getPrices(true));
console.log(getPrices(false));

  
// Implement getDiscount()

    function getDiscount(taxBoolean, guests) {   //Step 8
        getPrices(taxBoolean);                   //Step 9
        try {                                    //Step 10
            if (typeof (guests) != 'number' && (guests) < 0 && (guests) > 30) {  //Step 11
                var discount = 0;
                if (typeof (guests) < 5) {
                    discount = 5;
                }
                else if (typeof (guests) >= 5) {
                    discount = 10;
                    console.log('Discount is: $' + discount);
                }
                else {                                                          //step 12
                    console.log('the second argument must be a number between 0 and 30')
                }
            }
        } catch (err) { // Code throws error
            alert('catch', err);
        }
    }


//Call getDiscount();
getDiscount(true, 2);
getDiscount(false, 10)

Answer 1

Try this when taxed:

var finalPrice = 0;
dishData.forEach((dish)=>{
  finalPrice+=dish.price*tax;
})

Just remove the multiplication by tax when not being taxed, or if you want to simplify the code further try a one line if for taxBoolean :

var finalPrice = 0;
dishData.forEach((dish)=>{
  finalPrice+=dish.price * (taxBoolean ? tax : 1);
})

This makes it so you don't check for taxBoolean when getting the final price. Regarding the if statements in GetPrices you only need an if for true and an else for false , unless its some null or undefined type variable.

If for some reason you want to return the array of taxed prices instead of the total taxed price, use the map function for the dishData array.

var finalPrice = dishData.map((dish)=>dish.price*(taxBoolean ? tax : 1));

dishData is an array of objects not an object itself, so you need to iterate over it and add the price property multiplied with tax . Consider renaming dishData to dishes or something plural to show that its an array.

ALSO do not re-declare finalPrice either remove the var finalPrice = "" line or change it to var finalPrice=0; and remove the other var finalPrice = 0; in the if statements.

Answer 2

figured it out with a little help from a friend.

function getPrices(taxBoolean) {   //step1
   for (var i = 0; i < dishData.length; i++) {   // step 2
         let finalPrice = 0                                           // step 3
        if (taxBoolean == true) {                  // step 4
            let name = dishData[i]['name'];
            let price = dishData[i]['price'];  // Step 4
            finalPrice = price * tax
            console.log(`Dish: ${name}` + " " + `Price: $${finalPrice}`)      
        } else if (taxBoolean == false) {            //step 5
            let name = dishData[i]['name'];
            let price = dishData[i]['price'];
            //console.log('Prices without tax:');
            finalPrice = price
            console.log(`Dish: ${name}` + " " + `Price: $${finalPrice}`)
        } else {                                        //step 6
            console.log("You need to pass a boolean to the getPrices call!")
            return;
        }
    }
}
console.log(getPrices(true));
console.log(getPrices(false));


  
// Implement getDiscount()

    function getDiscount(taxBoolean, guests) {   //Step 8
        getPrices(taxBoolean);                   //Step 9
        try {                                    //Step 10
            if (typeof(guests) == 'number' && guests > 0 && guests < 30) {  //Step 11
                let discount = 0;
                    if (guests < 5) {
                        discount = 5;
                        console.log('Discount is: $' + discount);
                        
                    } else if (guests >= 5) {
                        discount = 10;
                        console.log('Discount is: $' + discount);
                    }
            } else {                                                          //step 12
                console.log('the second argument must be a number between 0 and 30');
            }
        } catch (err) { // Code throws error
            console.log('catch', err);
        }
    }
//Call getDiscount();

console.log(getDiscount(true, 2));
console.log(getDiscount(false, 10));