See the documentation on MDN about expressions and operators and statements.
this keyword:var x = function() vs. function x() — Function declaration syntax(function(){…})() — IIFE (Immediately Invoked Function Expression)(function(){…})(); work but function(){…}(); doesn't?(function(){…})(); vs (function(){…}());!function(){…}(); - What does the exclamation mark do before the function?+function(){…}(); - JavaScript plus sign in front of function expression! vs leading semicolon(function(window, undefined){…}(window));someFunction()() — Functions which return other functions=> — Equal sign, greater than: arrow function expression syntax|> — Pipe, greater than: Pipeline operatorfunction*, yield, yield* — Star after function or yield: generator functions[], Array() — Square brackets: array notationIf the square brackets appear on the left side of an assignment ([a] = ...), or inside a function's parameters, it's a destructuring assignment.
{key: value} — Curly brackets: object literal syntax (not to be confused with blocks)If the curly brackets appear on the left side of an assignment ({ a } = ...) or inside a function's parameters, it's a destructuring assignment.
`…${…}…` — Backticks, dollar sign with curly brackets: template literals`…${…}…` code from the node docs mean?/…/ — Slashes: regular expression literals$ — Dollar sign in regex replace patterns: $$, $&, $`, $', $n() — Parentheses: grouping operatorobj.prop, obj[prop], obj["prop"] — Square brackets or dot: property accessors?., ?.[], ?.() — Question mark, dot: optional chaining operator:: — Double colon: bind operatornew operator...iter — Three dots: spread syntax; rest parameters(...args) => {} — What is the meaning of “…args” (three dots) in a function definition?[...iter] — javascript es6 array feature […data, 0] “spread operator”{...props} — Javascript Property with three dots (…)++, -- — Double plus or minus: pre- / post-increment / -decrement operatorsdelete operatorvoid operator+, - — Plus and minus: addition or concatenation, and subtraction operators; unary sign operators|, &, ^, ~ — Single pipe, ampersand, circumflex, tilde: bitwise OR, AND, XOR, & NOT operators~1 equal -2?% — Percent sign: remainder operator&&, ||, ! — Double ampersand, double pipe, exclamation point: logical operators?? — Double question mark: nullish-coalescing operator** — Double star: power operator (exponentiation)x ** 2 is equivalent to Math.pow(x, 2)==, === — Equal signs: equality operators!=, !== — Exclamation point and equal signs: inequality operators<<, >>, >>> — Two or three angle brackets: bit shift operators?…:… — Question mark and colon: conditional (ternary) operator= — Equal sign: assignment operator%= — Percent equals: remainder assignment+= — Plus equals: addition assignment operator&&=, ||=, ??= — Double ampersand, pipe, or question mark, followed by equal sign: logical assignments||= (or equals) in JavaScript?, — Comma operator{…} — Curly brackets: blocks (not to be confused with object literal syntax)var, let, const — Declaring variableslabel: — Colon: labels# — Hash (number sign): Private methods or private fields