Curriculum Short Specializations Average: 0.0% 0x00. ES6 Basics JavaScript ES6 Weight: 1 Project will start Aug 5, 2024 5:00 AM, must end by Aug 6, 2024 5:00 AM Checker was released at Aug 5, 2024 11:00 AM An auto review will be launched at the deadline Concepts For this project, we expect you to look at these concepts:
JavaScript programming Software Linter
Resources Read or watch:
ECMAScript 6 - ECMAScript 2015 Statements and declarations Arrow functions Default parameters Rest parameter Javascript ES6 — Iterables and Iterators Learning Objectives At the end of this project, you are expected to be able to explain to anyone, without the help of Google:
What ES6 is New features introduced in ES6 The difference between a constant and a variable Block-scoped variables Arrow functions and function parameters default to them Rest and spread function parameters String templating in ES6 Object creation and their properties in ES6 Iterators and for-of loops Requirements General All your files will be executed on Ubuntu 18.04 LTS using NodeJS 12.11.x Allowed editors: vi, vim, emacs, Visual Studio Code All your files should end with a new line A README.md file, at the root of the folder of the project, is mandatory Your code should use the js extension Your code will be tested using the Jest Testing Framework Your code will be analyzed using the linter ESLint along with specific rules that we’ll provide All of your functions must be exported Setup Install NodeJS 12.11.x (in your home directory):
curl -sL https://deb.nodesource.com/setup_12.x -o nodesource_setup.sh sudo bash nodesource_setup.sh sudo apt install nodejs -y $ nodejs -v v12.11.1 $ npm -v 6.11.3 Install Jest, Babel, and ESLint in your project directory, install Jest, Babel and ESList by using the supplied package.json and run npm install.
Configuration files Add the files below to your project directory
package.json Click here to show/hide file contents
{ "scripts": { "lint": "./node_modules/.bin/eslint", "check-lint": "lint [0-9].js", "dev": "npx babel-node", "test": "jest", "full-test": "./node_modules/.bin/eslint [0-9].js && jest" }, "devDependencies": { "@babel/core": "^7.6.0", "@babel/node": "^7.8.0", "@babel/preset-env": "^7.6.0", "eslint": "^6.4.0", "eslint-config-airbnb-base": "^14.0.0", "eslint-plugin-import": "^2.18.2", "eslint-plugin-jest": "^22.17.0", "jest": "^24.9.0" } }
babel.config.js Click here to show/hide file contents
module.exports = { presets: [ [ '@babel/preset-env', { targets: { node: 'current', }, }, ], ], };
.eslintrc.js Click here to show/hide file contents
module.exports = { env: { browser: false, es6: true, jest: true, }, extends: [ 'airbnb-base', 'plugin:jest/all', ], globals: { Atomics: 'readonly', SharedArrayBuffer: 'readonly', }, parserOptions: { ecmaVersion: 2018, sourceType: 'module', }, plugins: ['jest'], rules: { 'no-console': 'off', 'no-shadow': 'off', 'no-restricted-syntax': [ 'error', 'LabeledStatement', 'WithStatement', ], }, overrides:[ { files: ['*.js'], excludedFiles: 'babel.config.js', } ] };
Finally… Don’t forget to run npm install from the terminal of your project folder to install all necessary project dependencies.
Tasks 0. Const or let? mandatory Modify
function taskFirst to instantiate variables using const function taskNext to instantiate variables using let export function taskFirst() { var task = 'I prefer const when I can.'; return task; }
export function getLast() { return ' is okay'; }
export function taskNext() { var combination = 'But sometimes let'; combination += getLast();
return combination; } Execution example:
bob@dylan:~$ cat 0-main.js import { taskFirst, taskNext } from './0-constants.js';
console.log(${taskFirst()} ${taskNext()});
bob@dylan:$
bob@dylan:$ npm run dev 0-main.js
I prefer const when I can. But sometimes let is okay
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 0-constants.js
- Block Scope mandatory Given what you’ve read about var and hoisting, modify the variables inside the function taskBlock so that the variables aren’t overwritten inside the conditional block.
export default function taskBlock(trueOrFalse) { var task = false; var task2 = true;
if (trueOrFalse) { var task = true; var task2 = false; }
return [task, task2]; } Execution:
bob@dylan:~$ cat 1-main.js import taskBlock from './1-block-scoped.js';
console.log(taskBlock(true));
console.log(taskBlock(false));
bob@dylan:$
bob@dylan:$ npm run dev 1-main.js
[ false, true ]
[ false, true ]
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 1-block-scoped.js
- Arrow functions mandatory Rewrite the following standard function to use ES6’s arrow syntax of the function add (it will be an anonymous function after)
export default function getNeighborhoodsList() { this.sanFranciscoNeighborhoods = ['SOMA', 'Union Square'];
const self = this; this.addNeighborhood = function add(newNeighborhood) { self.sanFranciscoNeighborhoods.push(newNeighborhood); return self.sanFranciscoNeighborhoods; }; } Execution:
bob@dylan:~$ cat 2-main.js import getNeighborhoodsList from './2-arrow.js';
const neighborhoodsList = new getNeighborhoodsList();
const res = neighborhoodsList.addNeighborhood('Noe Valley');
console.log(res);
bob@dylan:$
bob@dylan:$ npm run dev 2-main.js
[ 'SOMA', 'Union Square', 'Noe Valley' ]
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 2-arrow.js
- Parameter defaults mandatory Condense the internals of the following function to 1 line - without changing the name of each function/variable.
Hint: The key here to define default parameter values for the function parameters.
export default function getSumOfHoods(initialNumber, expansion1989, expansion2019) { if (expansion1989 === undefined) { expansion1989 = 89; }
if (expansion2019 === undefined) { expansion2019 = 19; } return initialNumber + expansion1989 + expansion2019; } Execution:
bob@dylan:~$ cat 3-main.js import getSumOfHoods from './3-default-parameter.js';
console.log(getSumOfHoods(34));
console.log(getSumOfHoods(34, 3));
console.log(getSumOfHoods(34, 3, 4));
bob@dylan:$
bob@dylan:$ npm run dev 3-main.js
142
56
41
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 3-default-parameter.js
- Rest parameter syntax for functions mandatory Modify the following function to return the number of arguments passed to it using the rest parameter syntax
export default function returnHowManyArguments() {
} Example:
returnHowManyArguments("Hello", "Holberton", 2020); 3
Execution:
bob@dylan:~$ cat 4-main.js import returnHowManyArguments from './4-rest-parameter.js';
console.log(returnHowManyArguments("one"));
console.log(returnHowManyArguments("one", "two", 3, "4th"));
bob@dylan:$
bob@dylan:$ npm run dev 4-main.js
1
4
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 4-rest-parameter.js
- The wonders of spread syntax mandatory Using spread syntax, concatenate 2 arrays and each character of a string by modifying the function below. Your function body should be one line long.
export default function concatArrays(array1, array2, string) { } Execution:
bob@dylan:~$ cat 5-main.js import concatArrays from './5-spread-operator.js';
console.log(concatArrays(['a', 'b'], ['c', 'd'], 'Hello'));
bob@dylan:$
bob@dylan:$ npm run dev 5-main.js
[
'a', 'b', 'c',
'd', 'H', 'e',
'l', 'l', 'o'
]
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 5-spread-operator.js
- Take advantage of template literals mandatory Rewrite the return statement to use a template literal so you can the substitute the variables you’ve defined.
export default function getSanFranciscoDescription() { const year = 2017; const budget = { income: '$119,868', gdp: '$154.2 billion', capita: '$178,479', };
return 'As of ' + year + ', it was the seventh-highest income county in the United States' / ', with a per capita personal income of ' + budget.income + '. As of 2015, San Francisco' / ' proper had a GDP of ' + budget.gdp + ', and a GDP per capita of ' + budget.capita + '.'; } Execution:
bob@dylan:~$ cat 6-main.js import getSanFranciscoDescription from './6-string-interpolation.js';
console.log(getSanFranciscoDescription());
bob@dylan:$
bob@dylan:$ npm run dev 6-main.js
As of 2017, it was the seventh-highest income county in the United States, with a per capita personal income of $119,868. As of 2015, San Francisco proper had a GDP of $154.2 billion, and a GDP per capita of
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 6-string-interpolation.js
- Object property value shorthand syntax mandatory Notice how the keys and the variable names are the same?
Modify the following function’s budget object to simply use the keyname instead.
export default function getBudgetObject(income, gdp, capita) { const budget = { income: income, gdp: gdp, capita: capita, };
return budget; } Execution:
bob@dylan:~$ cat 7-main.js import getBudgetObject from './7-getBudgetObject.js';
console.log(getBudgetObject(400, 700, 900));
bob@dylan:$
bob@dylan:$ npm run dev 7-main.js
{ income: 400, gdp: 700, capita: 900 }
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 7-getBudgetObject.js
- No need to create empty objects before adding in properties mandatory Rewrite the getBudgetForCurrentYear function to use ES6 computed property names on the budget object
function getCurrentYear() { const date = new Date(); return date.getFullYear(); }
export default function getBudgetForCurrentYear(income, gdp, capita) { const budget = {};
budget[income-${getCurrentYear()}] = income;
budget[gdp-${getCurrentYear()}] = gdp;
budget[capita-${getCurrentYear()}] = capita;
return budget; } Execution:
bob@dylan:~$ cat 8-main.js import getBudgetForCurrentYear from './8-getBudgetCurrentYear.js';
console.log(getBudgetForCurrentYear(2100, 5200, 1090));
bob@dylan:$
bob@dylan:$ npm run dev 8-main.js
{ 'income-2021': 2100, 'gdp-2021': 5200, 'capita-2021': 1090 }
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 8-getBudgetCurrentYear.js
- ES6 method properties mandatory Rewrite getFullBudgetObject to use ES6 method properties in the fullBudget object
import getBudgetObject from './7-getBudgetObject.js';
export default function getFullBudgetObject(income, gdp, capita) {
const budget = getBudgetObject(income, gdp, capita);
const fullBudget = {
...budget,
getIncomeInDollars: function (income) {
return $${income};
},
getIncomeInEuros: function (income) {
return ${income} euros;
},
};
return fullBudget; } Execution:
bob@dylan:~$ cat 9-main.js import getFullBudgetObject from './9-getFullBudget.js';
const fullBudget = getFullBudgetObject(20, 50, 10);
console.log(fullBudget.getIncomeInDollars(fullBudget.income)); console.log(fullBudget.getIncomeInEuros(fullBudget.income));
bob@dylan:$
bob@dylan:$ npm run dev 9-main.js
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 9-getFullBudget.js
- For...of Loops mandatory Rewrite the function appendToEachArrayValue to use ES6’s for...of operator. And don’t forget that var is not ES6-friendly.
export default function appendToEachArrayValue(array, appendString) { for (var idx in array) { var value = array[idx]; array[idx] = appendString + value; }
return array; } Execution:
bob@dylan:~$ cat 10-main.js import appendToEachArrayValue from './10-loops.js';
console.log(appendToEachArrayValue(['appended', 'fixed', 'displayed'], 'correctly-'));
bob@dylan:$
bob@dylan:$ npm run dev 10-main.js
[ 'correctly-appended', 'correctly-fixed', 'correctly-displayed' ]
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 10-loops.js
- Iterator mandatory Write a function named createEmployeesObject that will receive two arguments:
departmentName (String) employees (Array of Strings) export default function createEmployeesObject(departmentName, employees) {
} The function should return an object with the following format:
{ $departmentName: [ $employees, ], } Execution:
bob@dylan:~$ cat 11-main.js import createEmployeesObject from './11-createEmployeesObject.js';
console.log(createEmployeesObject("Software", [ "Bob", "Sylvie" ]));
bob@dylan:$
bob@dylan:$ npm run dev 11-main.js
{ Software: [ 'Bob', 'Sylvie' ] }
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 11-createEmployeesObject.js
- Let's create a report object mandatory Write a function named createReportObject whose parameter, employeesList, is the return value of the previous function createEmployeesObject.
export default function createReportObject(employeesList) {
} createReportObject should return an object containing the key allEmployees and a method property called getNumberOfDepartments.
allEmployees is a key that maps to an object containing the department name and a list of all the employees in that department. If you’re having trouble, use the spread syntax.
The method property receives employeesList and returns the number of departments. I would suggest suggest thinking back to the ES6 method property syntax.
{ allEmployees: { engineering: [ 'John Doe', 'Guillaume Salva', ], }, }; Execution:
bob@dylan:~$ cat 12-main.js import createEmployeesObject from './11-createEmployeesObject.js'; import createReportObject from './12-createReportObject.js';
const employees = { ...createEmployeesObject('engineering', ['Bob', 'Jane']), ...createEmployeesObject('marketing', ['Sylvie']) };
const report = createReportObject(employees); console.log(report.allEmployees); console.log(report.getNumberOfDepartments(report.allEmployees));
bob@dylan:$
bob@dylan:$ npm run dev 12-main.js
{ engineering: [ 'Bob', 'Jane' ], marketing: [ 'Sylvie' ] }
2
bob@dylan:~$
Repo:
GitHub repository: alx-backend-javascript Directory: 0x00-ES6_basic File: 12-createReportObject.js
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