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The conditional (ternary) operator (?:) is the only JavaScript operator that takes three operands. It evaluates a boolean condition and resolves to one of two expressions based on whether the condition’s result is truthy or falsy, functioning as an expression-based equivalent to the if...else control flow statement. 
condition ? expressionIfTrue : expressionIfFalse

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Operands and Evaluation

  1. condition: An expression evaluated in a boolean context. JavaScript applies implicit type coercion to determine if the evaluated result is truthy or falsy.
  2. expressionIfTrue: The expression evaluated and returned if the condition is truthy.
  3. expressionIfFalse: The expression evaluated and returned if the condition is falsy.

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Technical Characteristics

Expression vs. Statement Unlike if...else, which is a statement used for control flow, the ternary operator is an expression. It always evaluates to a distinct value. This allows the operator to be assigned to variables, returned directly from functions, or nested within larger expressions. Short-Circuit Evaluation The ternary operator guarantees short-circuit evaluation. The JavaScript engine evaluates the condition first, and then evaluates only the selected consequent expression. The unselected expression is entirely ignored, meaning any function calls or side effects within the ignored expression will not execute. 
const isTruthy = true;
const executeA = () => "A executed";
const executeB = () => "B executed";

// Because isTruthy is true, executeA() runs and executeB() is completely ignored.
const result = isTruthy ? executeA() : executeB();

console.log(result); // "A executed"
Right-Associativity The ternary operator is right-associative. When multiple ternary operators are chained together without explicit parentheses, the JavaScript engine groups and evaluates them from right to left. 
const condition1 = false;
const condition2 = true;

// Chained syntax
const result = condition1 ? "value1" 
             : condition2 ? "value2" 
             : "value3";

// How the engine implicitly groups the evaluation (Right-Associative)
const groupedResult = condition1 ? "value1" : (condition2 ? "value2" : "value3");

console.log(result); // "value2"
console.log(result === groupedResult); // true
Precedence The ternary operator has very low operator precedence, sitting just above assignment operators (=, +=, etc.) and the yield/comma operators. Because of this, complex expressions used as operands within a ternary operation generally do not require parentheses, though the condition itself is often wrapped in parentheses for readability.
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