Clean Code

Variables

Use default parameters instead of short circuiting or conditionals

Default parameters are often cleaner than short circuiting. Be aware that if you use them, your function will only provide default values for undefined arguments. Other "falsy" values such as '', "", false, null, 0, and NaN, will not be replaced by a default value.

Bad

function createMicrobrewery(name) {
  const breweryName = name || "Hipster Brew Co.";
  // ...
}

Better

function createMicrobrewery(name = "Hipster Brew Co.") {
  // ...
}

Functions

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);
  }
}

Better

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

function createTempFile(name) {
  createFile(`./temp/${name}`);
}

Avoid negative conditionals

Bad

function isDOMNodeNotPresent(node) {
  // ...
}

if (!isDOMNodeNotPresent(node)) {
  // ...
}

Better

function isDOMNodePresent(node) {
  // ...
}

if (isDOMNodePresent(node)) {
  // ...
}