Async Await Node

Author: Ashleshk

aynsc-await-node/.gitignore

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+.vscode
+node_modules

aynsc-await-node/app-promises.js

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+const users = [{
+  id: 1,
+  name: 'Andrew',
+  schoolId: 101
+}, {
+  id: 2,
+  name: 'Jessica',
+  schoolId: 999
+}];
+
+const grades = [{
+  id: 1,
+  schoolId: 101,
+  grade: 86
+}, {
+  id: 2,
+  schoolId: 999,
+  grade: 100
+}, {
+  id: 3,
+  schoolId: 101,
+  grade: 80
+}];
+
+const getUser = (id) => {
+  return new Promise((resolve, reject) => {
+    const user = users.find((user) => user.id === id);
+
+    if (user) {
+      resolve(user);
+    } else {
+      reject(`Unable to find user with id of ${id}.`);
+    }
+  });
+};
+
+const getGrades = (schoolId) => {
+  return new Promise((resolve, reject) => {
+    resolve(grades.filter((grade) => grade.schoolId === schoolId));
+  });
+};
+
+// Andrew has a 83% in the class
+const getStatus = (userId) => {
+  let user;
+  return getUser(userId).then((tempUser) => {
+    user = tempUser;
+    return getGrades(user.schoolId);
+  }).then((grades) => {
+    let average = 0;
+
+    if (grades.length > 0) {
+      average = grades.map((grade) => grade.grade).reduce((a, b) => a + b) / grades.length;
+    }
+
+    return `${user.name} has a ${average}% in the class.`;
+  });
+};
+
+const getStatusAlt = async (userId) => {
+  const user = await getUser(userId);
+  const grades = await getGrades(user.schoolId);
+  let average = 0;
+
+  if (grades.length > 0) {
+    average = grades.map((grade) => grade.grade).reduce((a, b) => a + b) / grades.length;
+  }
+
+  return `${user.name} has a ${average}% in the class.`;
+};
+
+getStatusAlt(2).then((status) => {
+  console.log(status);
+}).catch((e) => {
+  console.log(e);
+});
+
+// getStatus(123).then((status) => {
+//   console.log(status);
+// }).catch((e) => {
+//   console.log(e);
+// });

aynsc-await-node/currency-convert.js

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+const axios = require('axios');
+
+const getExchangeRate = async (from, to) => {
+  try {
+  const response = await axios.get('http://data.fixer.io/api/latest?access_key=28fb091f0ecba07964b7843abea0f119');
+  const euro = 1 / response.data.rates[from];
+  const rate = euro * response.data.rates[to];
+
+  if (isNaN(rate)) {
+    throw new Error();
+  }
+
+  return rate;
+} catch (e) {
+  throw new Error(`Unable to get exchange rate for ${from} and ${to}.`);
+}
+};
+
+const getCountries = async (currencyCode) => {
+  try {
+    const response = await axios.get(`https://restcountries.eu/rest/v2/currency/${currencyCode}`);
+    return response.data.map((country) => country.name);
+  } catch (e) {
+    throw new Error(`Unable to get countries that use ${currencyCode}.`)
+  }
+};
+
+const convertCurrency = async (from, to, amount) => {
+  const rate = await getExchangeRate(from, to);
+  const countries = await getCountries(to);
+  const convertedAmount = (amount * rate).toFixed(2); 
+  return `${amount} ${from} is worth ${convertedAmount} ${to}. You can spend it in the following countries:\n ${countries.join('\n ')}`;
+};
+
+convertCurrency('USD', 'CAD', 20).then((message) => {
+  console.log(message);
+}).catch((e) => {
+  console.log(e.message);
+});
+

aynsc-await-node/package-lock.json

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+{
+  "name": "aynsc-await-node",
+  "version": "1.0.0",
+  "description": "",
+  "main": "app-promises.js",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  },
+  "author": "",
+  "license": "ISC",
+  "dependencies": {
+    "axios": "^0.18.0"
+  }
+}