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192The Boolean Type and Its Two Values
193Boolean Literals in Code
194The Boolean() Constructor
195Truthy Values: What Evaluates to True
196Falsy Values: The Complete List
197Implicit Boolean Conversion in Conditionals
198Double Negation (!!) to Coerce to Boolean
199Empty Strings vs Strings with Whitespace
200Zero and Negative Zero
201null vs undefined in Boolean Context
202NaN: The Falsy Non-Number
203Common Truthy/Falsy Pitfalls
204Equality: == vs ===
205Inequality: != vs !==
206Greater Than and Less Than
207Greater/Less Than or Equal
208Comparing Numbers
209String Comparison
210Comparing Different Types
211Object and Array Comparison
212The Problem with NaN
213Chaining Comparisons
214The && (AND) Operator
215The || (OR) Operator
216The ! (NOT) Operator
217Short-Circuit Evaluation with &&
218Short-Circuit Evaluation with ||
219Using && for Conditional Execution
220Using || for Default Values
221Double Negation !! for Boolean Coercion
222Combining Multiple Logical Operators
223Logical Operators Return Operands, Not Booleans
224Common Pitfalls with 0 and Empty Strings
225Logical Operators in Conditions
226Avoiding Overuse of Logical Operators
227The Ternary Operator Syntax
228Ternary as an Expression
229When to Use Ternary vs If/Else
230Nested Ternaries
231Ternary Operator Precedence
232Common Ternary Patterns
233Ternary Pitfalls and Readability

192The Boolean Type and Its Two Values
193Boolean Literals in Code
194The Boolean() Constructor
195Truthy Values: What Evaluates to True
196Falsy Values: The Complete List
197Implicit Boolean Conversion in Conditionals
198Double Negation (!!) to Coerce to Boolean
199Empty Strings vs Strings with Whitespace
200Zero and Negative Zero
201null vs undefined in Boolean Context
202NaN: The Falsy Non-Number
203Common Truthy/Falsy Pitfalls
204Equality: == vs ===
205Inequality: != vs !==
206Greater Than and Less Than
207Greater/Less Than or Equal
208Comparing Numbers
209String Comparison
210Comparing Different Types
211Object and Array Comparison
212The Problem with NaN
213Chaining Comparisons
214The && (AND) Operator
215The || (OR) Operator
216The ! (NOT) Operator
217Short-Circuit Evaluation with &&
218Short-Circuit Evaluation with ||
219Using && for Conditional Execution
220Using || for Default Values
221Double Negation !! for Boolean Coercion
222Combining Multiple Logical Operators
223Logical Operators Return Operands, Not Booleans
224Common Pitfalls with 0 and Empty Strings
225Logical Operators in Conditions
226Avoiding Overuse of Logical Operators
227The Ternary Operator Syntax
228Ternary as an Expression
229When to Use Ternary vs If/Else
230Nested Ternaries
231Ternary Operator Precedence
232Common Ternary Patterns
233Ternary Pitfalls and Readability

Lesson 214 of 2,723·6. Booleans and ConditionalsPro lesson

The && (AND) Operator

Learn how && evaluates both operands and returns the first falsy value or the last value.

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