Mocha
Jest
AVA
Jasmine

Use var
Use only const and let

Declare all variables at the beginning
Declare variables just before using them

Semi-colon terminated statements
Don't use semi-colons

2 Spaces
4 Spaces
Tabs

Yes Always. const foo = [x, y, z,]
Multiline Only.
Never. const foo = [x, y, z]

Allow == and != . '1' == 1 -> true . ' ' == 0 -> true
Only Allow === and !== . '1' === 1 -> false . ' ' === 0 -> false

Use concatenation. "Hello " + firstname;
Use inline variables (ES6 only). `Hello ${firstname}`

Explicit new. const x = new Array(), const x = new Object()
Implicit. const x = [], const x = {};

snake_case
camelCase
PascalCase
MACRO_CASE

snake_case
camelCase
PascalCase
MACRO_CASE

snake_case
camelCase
PascalCase
MACRO_CASE

snake_case
camelCase
PascalCase
MACRO_CASE

snake_case
camelCase
PascalCase
MACRO_CASE