Your daily hit of JavaScript hacks, fixes, and mind popping tricks
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
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
How to Stop Map Keys From Being Auto-Stringified
Object keys coerce and collide.
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
How to Prevent parseInt From Truncating IDs
parseInt stops at non-digits and drops data.
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
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
Optional Chaining vs Try-Except: Null Safety Battle
JavaScript's ?. operator vs Python's try-except. Which language handles null/undefined more elegantly? Mind = blown!
#javascript #python #javascriptvspython #optionalchaining #nullsafety #errorhandling #programmingcomparison #codecomparison #javascripttricks #pythontricks #syntaxcomparison #viralcoding
Why does this JavaScript token become predictable?
Why does this JavaScript token become predictable in production. The JavaScript code uses Math.random for session tokens, which is not cryptographically secure. In JavaScript auth systems this enables session hijacking.
#whatswrongwiththisjavascriptcode #javascriptbug #javascriptproductionbug #javascriptdebugging #javascriptbackend #javascriptcodereview #javascriptsecurity #javascriptperformance ...
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
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
Why does this JavaScript SSL setting break security?
Why does this JavaScript SSL setting break security in a payment client. The JavaScript code disables certificate verification, which makes HTTPS vulnerable to MITM. In JavaScript services this exposes credentials.
#whatswrongwiththisjavascriptcode #javascriptbug #javascriptproductionbug #javascriptdebugging #javascriptbackend #javascriptcodereview #javascriptsecurity #javascriptperformance #ja...
How to Prevent Object Freeze From Being Bypassed
Freeze is shallow and nested objects still mutate.
How to Stop Destructuring From Crashing on null
Destructuring null throws instantly.
JS vs PHP Coupon Guard: Flash Sale Chaos Stopper
Detect repeat abusers and save your margins.
#php #javascript #couponabuse #flashsale #fraud #growth #viralcoding #codecomparison #ecommerce #revenue
Why does this JavaScript allowlist block valid users?
Why does this JavaScript allowlist block valid users. The JavaScript code checks indexOf and treats index 0 as false, so the first allowed user is rejected. In JavaScript access control this blocks legitimate requests.
#whatswrongwiththisjavascriptcode #javascriptbug #javascriptproductionbug #javascriptdebugging #javascriptbackend #javascriptcodereview #javascriptsecurity #javascriptperformanc...
Why does this JavaScript Promise.all lose writes?
Why does this JavaScript Promise.all lose writes in a fan out job. The JavaScript code allows one rejection to cancel all other promises. In JavaScript pipelines this causes partial writes and missing data.
#whatswrongwiththisjavascriptcode #javascriptbug #javascriptproductionbug #javascriptdebugging #javascriptbackend #javascriptcodereview #javascriptsecurity #javascriptperformance #javascriptrel...
How to Stop Map Mutation During Iteration
Mutating a Map while iterating is dangerous.
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