Statements and declarations - JavaScript | MDN

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JavaScript code is built from statements and declarations, which can contain expressions. This reference groups the constructs used to control execution and declare bindings. A statement can span multiple lines, and a line can contain multiple statements.
For an alphabetical listing see the sidebar on the left.
Specifies the value to be returned by a function.
Terminates the current loop, switch, or label statement and transfers program control to the statement following the terminated statement.
Terminates execution of the statements in the current iteration of the current or labeled loop, and continues execution of the loop with the next iteration.
Throws a user-defined exception.
Executes a statement if a specified condition is true. If the condition is false, another statement can be executed.
Evaluates an expression, matching the expression's value to a case clause, and executes statements associated with that case.
Marks a block of statements to try, and specifies a response, should an exception be thrown.
Declares a variable, optionally initializing it to a value.
Declares a block-scoped variable, optionally initializing it to a value.
Declares a block-scoped variable that cannot be re-assigned, which must be initialized at declaration.
Declares a variable like const that is synchronously disposed.
Declares a variable like const that is asynchronously disposed.
Declares a function with the specified parameters.
Generator Functions enable writing iterators more easily.
Declares an async function with the specified parameters.
Asynchronous Generator Functions enable writing async iterators more easily.
Creates a loop that executes a specified statement until the test condition evaluates to false. The condition is evaluated after executing the statement, resulting in the specified statement executing at least once.
Creates a loop that consists of three optional expressions, enclosed in parentheses and separated by semicolons, followed by a statement executed in the loop.
Iterates over the enumerable properties of an object, in arbitrary order. For each distinct property, statements can be executed.
Iterates over iterable objects (including arrays, array-like objects, iterators and generators), invoking a custom iteration hook with statements to be executed for the value of each distinct property.
Iterates over async iterable objects, array-like objects, iterators and generators, invoking a custom iteration hook with statements to be executed for the value of each distinct property.
Creates a loop that executes a specified statement as long as the test condition evaluates to true. The condition is evaluated before executing the statement.
An empty statement is used to provide no statement, although the JavaScript syntax would expect one.
A block statement is used to group zero or more statements. The block is delimited by a pair of curly braces.
An expression statement evaluates an expression and discards its result. It allows the expression to perform side effects, such as executing a function or updating a variable.
Invokes any available debugging functionality. If no debugging functionality is available, this statement has no effect.
Used to export functions to make them available for imports in external modules, and other scripts.
Used to import functions exported from an external module, another script.
Loads a module as a namespace, deferring synchronous evaluation until the returned namespace's properties are accessed.
Results in an object representing the module's compiled source, without loading its dependencies, linking it, or evaluating it.
Provides a statement with an identifier that you can refer to using a break or continue statement.
Extends the scope chain for a statement.