es6

arrow functions
let, const
deconstruction
default values
for (const item of list)
template strings incl tagged template strings

features

boxed values

f.e. 42 is unboxed, while Number(42) is boxed. valueOf() unboxes.

`apply` foo

Math.floor.apply(undefined, [1.75])
Function.prototype.apply.call(Math.floor, undefined, [1.75])
Reflect.apply(Math.floor, undefined, [1.75])

global

get global object with

(0, eval)('this')
(0 || eval)('this')
var e = eval; e('this')
[eval][0]('this')
eval('eval')('this')
{eval: eval}.eval('this')

eval usually executes in calling environment's scope, this is global object, undefined (strict mode) or whatever is bound. lose context and execute in global scope via indirect calls (0, eval) or var e = eval (expressions execute GetValue and yield values instead of references). that's similar to how var f = obj.func; f() and (0, obj.func)() lose their context.

nvm

specific version: nvm alias default 16.15.0. latest: nvm alias default node.

npm

execute locally installed scripts via npx. list all avail scripts w/ npm run. ntl is interactive script selector (npm i -g ntl).

npm view eslint versions, list available versions
npm install botstrap@3, specify version number
npm ls --depth 0 list installed packages, depth includes subdependencies, also respects -g
npm repo [<package>] opens current or given package repo in browser
npm link install globally via symlink
npm link <name> install from global as symlink
is it possible to link to other local package?
npm <command> --prefix <path> execute in another cwd
npm outdated list current, wanted (follows restrictions) and latest (maybe major)
npm update updated to lates "wanted"
npx npm-check-updates -u updates package.json

packages

es6 / es2015, import/export
commonjs, module.eports/require, 2009
amd, define, <=2010
umd, browser foo w/ iif factory pattern

unit tests

test runner

karma
mocha-cli
mocha-webpack
jasmine
none?

test framework

mocha
jasmine

assertions

chai
node assert
expect.js

utils

sinon: spies, stubs and mocks, brings own assertions
chai-sinon: integrates sinon assertions into expect-style chai assertions
sinon-chai-in-order: check for function calls in specific order

es6