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| 1 | +'use strict'; |
| 2 | + |
| 3 | +// Task: rewrite error handling to use callback-last-error-first |
| 4 | +// contract to return errors instead of throwing them. |
| 5 | +// So remove all try/catch blocks and pass errors to callbacks. |
| 6 | +// Hint: You may also use error.cause to wrap escalated errors. |
| 7 | +// Extra credit task: use AggregateError to combine escalated errors. |
| 8 | +// Extra credit task: fix eslint error: "Function declared in a loop |
| 9 | +// contains unsafe references to variable(s) 'total' no-loop-func" |
| 10 | + |
| 11 | +const MAX_PURCHASE = 2000; |
| 12 | + |
| 13 | +const calculateSubtotal = (goods, callback) => { |
| 14 | + let amount = 0; |
| 15 | + for (const item of goods) { |
| 16 | + if (typeof item.name !== 'string') { |
| 17 | + throw new Error('Noname in item in the bill'); |
| 18 | + } |
| 19 | + if (typeof item.price !== 'number') { |
| 20 | + throw new Error(`${item.name} price expected to be number`); |
| 21 | + } |
| 22 | + if (item.price < 0) { |
| 23 | + throw new Error(`Negative price for ${item.name}`); |
| 24 | + } |
| 25 | + amount += item.price; |
| 26 | + } |
| 27 | + callback(amount); |
| 28 | +}; |
| 29 | + |
| 30 | +const calculateTotal = (order, callback) => { |
| 31 | + const expenses = new Map(); |
| 32 | + let total = 0; |
| 33 | + for (const groupName in order) { |
| 34 | + const goods = order[groupName]; |
| 35 | + calculateSubtotal(goods, (amount) => { |
| 36 | + total += amount; |
| 37 | + expenses.set(groupName, amount); |
| 38 | + }); |
| 39 | + if (total > MAX_PURCHASE) { |
| 40 | + throw new Error('Total is above the limit'); |
| 41 | + } |
| 42 | + } |
| 43 | + return callback({ total, expenses }); |
| 44 | +}; |
| 45 | + |
| 46 | +const purchase = { |
| 47 | + Electronics: [ |
| 48 | + { name: 'Laptop', price: 1500 }, |
| 49 | + { name: 'Keyboard', price: 100 }, |
| 50 | + { name: 'HDMI cable' }, |
| 51 | + ], |
| 52 | + Textile: [ |
| 53 | + { name: 'Bag', price: 50 }, |
| 54 | + { price: 20 }, |
| 55 | + ], |
| 56 | +}; |
| 57 | + |
| 58 | +try { |
| 59 | + console.log(purchase); |
| 60 | + calculateTotal(purchase, (bill) => { |
| 61 | + console.log(bill); |
| 62 | + }); |
| 63 | +} catch (error) { |
| 64 | + console.log('Error detected'); |
| 65 | + console.error(error); |
| 66 | +} |
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