JavaScript distinguishes expressions and statements. An expression is any valid unit of code that resolves to a value. A statement is a unit of code that performs an action. Some examples:
// Statements
let x = 0;
function add(a, b) { return a + b; }
if (true) { console.log('Hi'); }
// Expressions
x; // Resolves to 0
3 + x; // Resolves to 3
add(1, 2); // Resolves to 3Anywhere JavaScript expects a statement, you can also write an expression. This kind of statement is called an expression statement. Conversely, you cannot write a statement where JavaScript expects an expression.
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