• Do you use tabs or space to indent? A
showed that the
majority of programmers prefer tabs, but that more experienced programmers
prefer spaces. I will let you choose your own path here….
• Do you prefer single or double quotes for strings? It doesn’t matter what you
answer here…we want to be able to use either equally.
• What line endings do you use (Unix or Windows)? If you’re on Linux or OS X,
choose Unix. If you’re on Windows, choose Windows.
• Do you require semicolons? Yes.
• Are you using ECMAScript 6 (ES6) features? Yes.
• Where will your code run (Node or in the browser)? Ideally, you would use a dif‐
ferent configuration for browser and Node code, but that’s a more advanced con‐
figuration. Go ahead and choose Node.
• Do you want to use JSX? No. (JSX is a XML-based extension to JavaScript that is
used in Facebook’s React UI library. We won’t be using it in this book.)
• What format do you want your config file to be in (JSON or YAML)? Choose
JSON (YAML is a popular data serialization format like JSON, but JSON is more
appropriate for JavaScript development).
After you’ve answered all the questions, you will have a .eslintrc file, and we can start
using ESLint.
There are several ways to run ESLint. You can run it directly (for example,
eslint
es6/test.js
), integrate into your editor, or add it to your Gulpfile. Editor integration
is great, but the instructions differ for every editor and operating system: if you want
editor integration, I recommend Googling the name of your editor with “eslint.”
Whether or not you use editor integration, I recommend adding ESLint to your
Gulpfile. After all, we have to run Gulp when we want to build, so that’s also a great
time to check the quality of our code. First, run:
npm
install
--
save
-
dev
gulp
-
eslint
Then modify gulpfile.js:
const
gulp
=
require
(
'gulp'
);
const
babel
=
require
(
'gulp-babel'
);
const
eslint
=
require
(
'gulp-eslint'
);
gulp
.
task
(
'default'
,
function
() {
// Run ESLint
gulp
.
src
([
"es6/**/*.js"
,
"public/es6/**/*.js"
])
.
pipe
(
eslint
())
.
pipe
(
eslint
.
format
());
// Node source
gulp
.
src
(
"es6/**/*.js"
)
28 | Chapter 2: JavaScript Development Tools
