#javascriptshorts — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #javascriptshorts, aggregated by home.social.
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You Can Use Same Variable Name TWICE?!
🔥 NO WAY! Destructuring allows DUPLICATE variable names in the same statement! const {a, a} = obj is VALID JavaScript! Last one silently wins. ESLint doesn't catch this by default. Tag a dev who needs to see this!
#javascript #javascripttricks #codingchallenge #destructuring #javascriptes6 #javascriptquiz #javascriptweird #javascriptwtf #javascriptbugs #codinginterview #codingtips #javascriptshorts
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flatMap Can Filter AND Transform?!
flatMap is a SECRET WEAPON! Return empty array to REMOVE items, return array with value to KEEP. One pass does filter AND map together! This trick will make your code 10x cleaner!
#javascript #javascripttricks #flatmap #arrayfilter #arraytransformation #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascripttips #functionalprogramming #advancedjavascript
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Promise.resolve UNWRAPS Thenables?!
Promise.resolve has RECURSIVE unwrapping! Any object with a 'then' method gets called. Nested thenables unwrap ALL the way down until a real value appears. This automatic unwrapping will confuse your async code!
#javascript #javascripttricks #promise.resolve #thenables #asyncunwrapping #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #promisequirks #advancedjavascript
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Math.min() > Math.max() Returns TRUE?!
⚠️ YOUR BRAIN WILL EXPLODE! Math.min() is GREATER than Math.max()! This breaks EVERY rule of mathematics! The answer will shock you. 97% of developers get this wrong!
#javascript #javascripttricks #codingchallenge #math.min #math.max #javascriptquiz #javascriptweird #javascriptwtf #mindblown #javascriptbugs #codingtips #javascriptshorts
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Math.min() > Math.max() Returns TRUE?!
⚠️ YOUR BRAIN WILL EXPLODE! Math.min() is GREATER than Math.max()! This breaks EVERY rule of mathematics! The answer will shock you. 97% of developers get this wrong!
#javascript #javascripttricks #codingchallenge #math.min #math.max #javascriptquiz #javascriptweird #javascriptwtf #mindblown #javascriptbugs #codingtips #javascriptshorts
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Math.min() > Math.max() Returns TRUE?!
⚠️ YOUR BRAIN WILL EXPLODE! Math.min() is GREATER than Math.max()! This breaks EVERY rule of mathematics! The answer will shock you. 97% of developers get this wrong!
#javascript #javascripttricks #codingchallenge #math.min #math.max #javascriptquiz #javascriptweird #javascriptwtf #mindblown #javascriptbugs #codingtips #javascriptshorts
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Math.min() > Math.max() Returns TRUE?!
⚠️ YOUR BRAIN WILL EXPLODE! Math.min() is GREATER than Math.max()! This breaks EVERY rule of mathematics! The answer will shock you. 97% of developers get this wrong!
#javascript #javascripttricks #codingchallenge #math.min #math.max #javascriptquiz #javascriptweird #javascriptwtf #mindblown #javascriptbugs #codingtips #javascriptshorts
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Math.min() > Math.max() Returns TRUE?!
⚠️ YOUR BRAIN WILL EXPLODE! Math.min() is GREATER than Math.max()! This breaks EVERY rule of mathematics! The answer will shock you. 97% of developers get this wrong!
#javascript #javascripttricks #codingchallenge #math.min #math.max #javascriptquiz #javascriptweird #javascriptwtf #mindblown #javascriptbugs #codingtips #javascriptshorts
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Arrow Functions Have NO arguments?!
Arrow functions BREAK arguments! They don't have the arguments object. This will cause ReferenceError when you try to use it. Regular functions work, arrows don't!
#javascript #javascripttricks #arrowfunctions #argumentsobject #thisbinding #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #functiondifferences #advancedjavascript
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Reflect API Shows HIDDEN Properties?!
Reflect.ownKeys REVEALS secrets! It shows non-enumerable properties that Object.keys hides. This is how you see ALL properties, even hidden ones!
#javascript #javascripttricks #reflectapi #propertyenumeration #hiddenproperties #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #reflection #advancedjavascript
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Reflect API Shows HIDDEN Properties?!
Reflect.ownKeys REVEALS secrets! It shows non-enumerable properties that Object.keys hides. This is how you see ALL properties, even hidden ones!
#javascript #javascripttricks #reflectapi #propertyenumeration #hiddenproperties #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #reflection #advancedjavascript
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Reflect API Shows HIDDEN Properties?!
Reflect.ownKeys REVEALS secrets! It shows non-enumerable properties that Object.keys hides. This is how you see ALL properties, even hidden ones!
#javascript #javascripttricks #reflectapi #propertyenumeration #hiddenproperties #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #reflection #advancedjavascript
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Reflect API Shows HIDDEN Properties?!
Reflect.ownKeys REVEALS secrets! It shows non-enumerable properties that Object.keys hides. This is how you see ALL properties, even hidden ones!
#javascript #javascripttricks #reflectapi #propertyenumeration #hiddenproperties #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #reflection #advancedjavascript
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Reflect API Shows HIDDEN Properties?!
Reflect.ownKeys REVEALS secrets! It shows non-enumerable properties that Object.keys hides. This is how you see ALL properties, even hidden ones!
#javascript #javascripttricks #reflectapi #propertyenumeration #hiddenproperties #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #reflection #advancedjavascript
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void Operator Returns WHAT?!
🤯 MIND BLOWN! The void operator ALWAYS returns undefined, no matter what! void(1+2+3) = undefined! This ancient JavaScript feature is still used in modern code. 95% of devs don't know this exists!
#javascript #javascripttricks #codingchallenge #voidoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #javascriptsecrets #codingtips #javascriptshorts
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void Operator Returns WHAT?!
🤯 MIND BLOWN! The void operator ALWAYS returns undefined, no matter what! void(1+2+3) = undefined! This ancient JavaScript feature is still used in modern code. 95% of devs don't know this exists!
#javascript #javascripttricks #codingchallenge #voidoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #javascriptsecrets #codingtips #javascriptshorts
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void Operator Returns WHAT?!
🤯 MIND BLOWN! The void operator ALWAYS returns undefined, no matter what! void(1+2+3) = undefined! This ancient JavaScript feature is still used in modern code. 95% of devs don't know this exists!
#javascript #javascripttricks #codingchallenge #voidoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #javascriptsecrets #codingtips #javascriptshorts
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void Operator Returns WHAT?!
🤯 MIND BLOWN! The void operator ALWAYS returns undefined, no matter what! void(1+2+3) = undefined! This ancient JavaScript feature is still used in modern code. 95% of devs don't know this exists!
#javascript #javascripttricks #codingchallenge #voidoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #javascriptsecrets #codingtips #javascriptshorts
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void Operator Returns WHAT?!
🤯 MIND BLOWN! The void operator ALWAYS returns undefined, no matter what! void(1+2+3) = undefined! This ancient JavaScript feature is still used in modern code. 95% of devs don't know this exists!
#javascript #javascripttricks #codingchallenge #voidoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #javascriptsecrets #codingtips #javascriptshorts
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Constructor Can Return DIFFERENT Object?!
Constructors can LIE about what they create! If you return an object, it REPLACES the instance. The 'new' keyword becomes USELESS. instanceof returns false! This breaks OOP principles!
#javascript #javascripttricks #constructor #classsyntax #instanceof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #oopquirks #advancedjavascript
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Constructor Can Return DIFFERENT Object?!
Constructors can LIE about what they create! If you return an object, it REPLACES the instance. The 'new' keyword becomes USELESS. instanceof returns false! This breaks OOP principles!
#javascript #javascripttricks #constructor #classsyntax #instanceof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #oopquirks #advancedjavascript
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Constructor Can Return DIFFERENT Object?!
Constructors can LIE about what they create! If you return an object, it REPLACES the instance. The 'new' keyword becomes USELESS. instanceof returns false! This breaks OOP principles!
#javascript #javascripttricks #constructor #classsyntax #instanceof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #oopquirks #advancedjavascript
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Constructor Can Return DIFFERENT Object?!
Constructors can LIE about what they create! If you return an object, it REPLACES the instance. The 'new' keyword becomes USELESS. instanceof returns false! This breaks OOP principles!
#javascript #javascripttricks #constructor #classsyntax #instanceof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #oopquirks #advancedjavascript
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Constructor Can Return DIFFERENT Object?!
Constructors can LIE about what they create! If you return an object, it REPLACES the instance. The 'new' keyword becomes USELESS. instanceof returns false! This breaks OOP principles!
#javascript #javascripttricks #constructor #classsyntax #instanceof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #oopquirks #advancedjavascript
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typeof Works in Temporal Dead Zone?!
Temporal Dead Zone has a LOOPHOLE! typeof works on undeclared variables (returns undefined) but throws ReferenceError for let/const. This inconsistency is INSANE!
#javascript #javascripttricks #tdz #temporaldeadzone #typeof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #variablehoisting #advancedjavascript
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typeof Works in Temporal Dead Zone?!
Temporal Dead Zone has a LOOPHOLE! typeof works on undeclared variables (returns undefined) but throws ReferenceError for let/const. This inconsistency is INSANE!
#javascript #javascripttricks #tdz #temporaldeadzone #typeof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #variablehoisting #advancedjavascript
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typeof Works in Temporal Dead Zone?!
Temporal Dead Zone has a LOOPHOLE! typeof works on undeclared variables (returns undefined) but throws ReferenceError for let/const. This inconsistency is INSANE!
#javascript #javascripttricks #tdz #temporaldeadzone #typeof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #variablehoisting #advancedjavascript
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typeof Works in Temporal Dead Zone?!
Temporal Dead Zone has a LOOPHOLE! typeof works on undeclared variables (returns undefined) but throws ReferenceError for let/const. This inconsistency is INSANE!
#javascript #javascripttricks #tdz #temporaldeadzone #typeof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #variablehoisting #advancedjavascript
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typeof Works in Temporal Dead Zone?!
Temporal Dead Zone has a LOOPHOLE! typeof works on undeclared variables (returns undefined) but throws ReferenceError for let/const. This inconsistency is INSANE!
#javascript #javascripttricks #tdz #temporaldeadzone #typeof #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #variablehoisting #advancedjavascript
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Array(3) vs [,,,] Are NOT The Same!
Creating arrays in JavaScript has a hidden trap! Array(3) and [,,,] look identical but behave completely differently. Mind blown!
#javascript #javascripttricks #codingtips #programmingtutorial #arrayconstructor #javascriptquiz #codingchallenge #javascriptshorts #javascriptbugs #sparsearrays #javascriptwtf #arraycreation
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Array(3) vs [,,,] Are NOT The Same!
Creating arrays in JavaScript has a hidden trap! Array(3) and [,,,] look identical but behave completely differently. Mind blown!
#javascript #javascripttricks #codingtips #programmingtutorial #arrayconstructor #javascriptquiz #codingchallenge #javascriptshorts #javascriptbugs #sparsearrays #javascriptwtf #arraycreation
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Array(3) vs [,,,] Are NOT The Same!
Creating arrays in JavaScript has a hidden trap! Array(3) and [,,,] look identical but behave completely differently. Mind blown!
#javascript #javascripttricks #codingtips #programmingtutorial #arrayconstructor #javascriptquiz #codingchallenge #javascriptshorts #javascriptbugs #sparsearrays #javascriptwtf #arraycreation
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Array(3) vs [,,,] Are NOT The Same!
Creating arrays in JavaScript has a hidden trap! Array(3) and [,,,] look identical but behave completely differently. Mind blown!
#javascript #javascripttricks #codingtips #programmingtutorial #arrayconstructor #javascriptquiz #codingchallenge #javascriptshorts #javascriptbugs #sparsearrays #javascriptwtf #arraycreation
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Array(3) vs [,,,] Are NOT The Same!
Creating arrays in JavaScript has a hidden trap! Array(3) and [,,,] look identical but behave completely differently. Mind blown!
#javascript #javascripttricks #codingtips #programmingtutorial #arrayconstructor #javascriptquiz #codingchallenge #javascriptshorts #javascriptbugs #sparsearrays #javascriptwtf #arraycreation
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Comma Operator Returns LAST Value Only?!
⚠️ THIS IS INSANE! The comma operator evaluates ALL expressions but returns ONLY the last one! (1,2,3,4,5) = 5! Used in for loops everywhere but nobody notices. Tag a dev who needs this!
#javascript #javascripttricks #codingchallenge #commaoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #forloops #codinginterview #javascriptshorts
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Comma Operator Returns LAST Value Only?!
⚠️ THIS IS INSANE! The comma operator evaluates ALL expressions but returns ONLY the last one! (1,2,3,4,5) = 5! Used in for loops everywhere but nobody notices. Tag a dev who needs this!
#javascript #javascripttricks #codingchallenge #commaoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #forloops #codinginterview #javascriptshorts
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Comma Operator Returns LAST Value Only?!
⚠️ THIS IS INSANE! The comma operator evaluates ALL expressions but returns ONLY the last one! (1,2,3,4,5) = 5! Used in for loops everywhere but nobody notices. Tag a dev who needs this!
#javascript #javascripttricks #codingchallenge #commaoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #forloops #codinginterview #javascriptshorts
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Comma Operator Returns LAST Value Only?!
⚠️ THIS IS INSANE! The comma operator evaluates ALL expressions but returns ONLY the last one! (1,2,3,4,5) = 5! Used in for loops everywhere but nobody notices. Tag a dev who needs this!
#javascript #javascripttricks #codingchallenge #commaoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #forloops #codinginterview #javascriptshorts
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Comma Operator Returns LAST Value Only?!
⚠️ THIS IS INSANE! The comma operator evaluates ALL expressions but returns ONLY the last one! (1,2,3,4,5) = 5! Used in for loops everywhere but nobody notices. Tag a dev who needs this!
#javascript #javascripttricks #codingchallenge #commaoperator #javascriptoperators #javascriptquiz #javascriptweird #javascriptwtf #forloops #codinginterview #javascriptshorts
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with() Changes Variable Scope?!
💥 DEPRECATED BUT STILL WORKS! The 'with' statement changes your scope and makes variables magically refer to object properties! Banned in strict mode but still in old codebases. This caused HUGE security bugs!
#javascript #javascripttricks #codingchallenge #withstatement #scope #javascriptquiz #javascriptweird #javascriptwtf #deprecated #javascriptbugs #javascriptshorts
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with() Changes Variable Scope?!
💥 DEPRECATED BUT STILL WORKS! The 'with' statement changes your scope and makes variables magically refer to object properties! Banned in strict mode but still in old codebases. This caused HUGE security bugs!
#javascript #javascripttricks #codingchallenge #withstatement #scope #javascriptquiz #javascriptweird #javascriptwtf #deprecated #javascriptbugs #javascriptshorts
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with() Changes Variable Scope?!
💥 DEPRECATED BUT STILL WORKS! The 'with' statement changes your scope and makes variables magically refer to object properties! Banned in strict mode but still in old codebases. This caused HUGE security bugs!
#javascript #javascripttricks #codingchallenge #withstatement #scope #javascriptquiz #javascriptweird #javascriptwtf #deprecated #javascriptbugs #javascriptshorts
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with() Changes Variable Scope?!
💥 DEPRECATED BUT STILL WORKS! The 'with' statement changes your scope and makes variables magically refer to object properties! Banned in strict mode but still in old codebases. This caused HUGE security bugs!
#javascript #javascripttricks #codingchallenge #withstatement #scope #javascriptquiz #javascriptweird #javascriptwtf #deprecated #javascriptbugs #javascriptshorts
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with() Changes Variable Scope?!
💥 DEPRECATED BUT STILL WORKS! The 'with' statement changes your scope and makes variables magically refer to object properties! Banned in strict mode but still in old codebases. This caused HUGE security bugs!
#javascript #javascripttricks #codingchallenge #withstatement #scope #javascriptquiz #javascriptweird #javascriptwtf #deprecated #javascriptbugs #javascriptshorts
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Object Keys Get AUTO-SORTED?!
Object key order is NOT guaranteed! Numeric string keys get SORTED before other keys. You add 'b' first but '1' appears first in Object.keys()! This auto-sorting will DESTROY your expected order!
#javascript #javascripttricks #object.keys #keyordering #numerickeys #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #objectquirks #advancedjavascript
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Object Keys Get AUTO-SORTED?!
Object key order is NOT guaranteed! Numeric string keys get SORTED before other keys. You add 'b' first but '1' appears first in Object.keys()! This auto-sorting will DESTROY your expected order!
#javascript #javascripttricks #object.keys #keyordering #numerickeys #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #objectquirks #advancedjavascript
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Object Keys Get AUTO-SORTED?!
Object key order is NOT guaranteed! Numeric string keys get SORTED before other keys. You add 'b' first but '1' appears first in Object.keys()! This auto-sorting will DESTROY your expected order!
#javascript #javascripttricks #object.keys #keyordering #numerickeys #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #objectquirks #advancedjavascript
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Object Keys Get AUTO-SORTED?!
Object key order is NOT guaranteed! Numeric string keys get SORTED before other keys. You add 'b' first but '1' appears first in Object.keys()! This auto-sorting will DESTROY your expected order!
#javascript #javascripttricks #object.keys #keyordering #numerickeys #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #objectquirks #advancedjavascript
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Object Keys Get AUTO-SORTED?!
Object key order is NOT guaranteed! Numeric string keys get SORTED before other keys. You add 'b' first but '1' appears first in Object.keys()! This auto-sorting will DESTROY your expected order!
#javascript #javascripttricks #object.keys #keyordering #numerickeys #javascriptweird #javascriptquiz #codingchallenge #javascriptshorts #javascriptwtf #objectquirks #advancedjavascript
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Labels Let You BREAK NESTED Loops?!
🔥 SECRET FEATURE! You can break out of nested loops using labels! outer: for... break outer; This skips BOTH loops at once! Senior devs don't even know this. Save this for your next interview!
#javascript #javascripttricks #codingchallenge #labeledstatements #breakstatement #nestedloops #javascriptquiz #javascriptweird #codinginterview #codingtips #javascriptshorts