clean-code-javascript/README.md

clean-code-javascript

Software engineering principles, from Robert C. Martin's wonderful book Clean Code, adapted for JavaScript.

Variables

Use meaningful and pronounceable variable names

Bad:

var yyyymmdstr = moment().format('YYYY/MM/DD');

Good:

var yearMonthDay = moment().format('YYYY/MM/DD');

Use the same vocabulary for the same type of variable

Bad:

getUserInfo();
getClientData();
getCustomerRecord();

Good:

getUser();

Functions

Limit the amount of function parameters (2 or less)

Use an object if you are finding yourself needing a lot of parameters

Bad:

function createMenu(title, body, buttonText, cancellable) {
  ...
}

Good:

var menuConfig = {
  title: 'Foo',
  body: 'Bar',
  buttonText: 'Baz'
  cancellable: true
}

function createMenu(config) {
  ...
}

Don't use flags as function parameters

Flags tell your user that this function does more than one thing. Functions should do one thing. Split out your functions if they are following different code paths based on a boolean.

Bad:

function createFile(name, temp) {
  if (temp) {
    fs.create('./temp/' + name);
  } else {
    fs.create(name);
  }
}

Good:

function createTempFile(name) {
  fs.create('./temp/' + name);
}

function createFile(name) {
  fs.create(name);
}

Comments

Only comment things that have business logic complexity.

Comments are an apology, not a requirement. Good code mostly documents itself.

Bad:

function hashIt(data) {
  // The hash
  var hash = 0;

  // Length of string
  var length = data.length;

  // Loop through every character in data
  for (var i = 0; i < length; i++) {
    // Get character code.
    var char = i.charCodeAt(i);
    // Make the hash
    hash = ((hash << 5) - hash) + char;
    // Convert to 32-bit integer
    hash = hash & hash;
  }
}

Good:

function hashIt(data) {
  var hash = 0;
  var length = data.length;

  for (var i = 0; i < length; i++) {
    var char = i.charCodeAt(i);
    hash = ((hash << 5) - hash) + char;

    // Convert to 32-bit integer
    hash = hash & hash;
  }
}