Why does this JavaScript trim not removing all whitespace?
Why does this JavaScript trim not removing all whitespace. The JavaScript code uses trim on user input. In JavaScript trim only handles space tab newline not unicode spaces.
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How to Stop instanceof From Lying Across Frames
Objects from iframes fail instanceof checks.
How to Use Queue With shift and push
FIFO. shift for dequeue. push for enqueue.
How to Stop JSON Stringify From Dropping BigInt
JSON.stringify throws on BigInt and breaks APIs.
What's wrong with this JavaScript BigInt mixing with Number?
What's wrong with this JavaScript BigInt mixing with Number in a calculator. The JavaScript code adds BigInt and Number. In JavaScript this throws and crashes the app.
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What's wrong with this JavaScript Object.assign overwriting?
What's wrong with this JavaScript Object.assign overwriting nested objects. The JavaScript code uses Object.assign for config merge. In JavaScript nested objects are copied by reference and get overwritten.
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Why does this JavaScript NaN break every comparison?
Why does this JavaScript NaN break every comparison in a validator. The JavaScript code uses === to check for NaN but NaN is not equal to itself. In JavaScript forms invalid numbers pass silently.
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How to Get Unique Values in One Line
Set removes duplicates. Spread back to array. No loop.
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!
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How to Use Symbol for Unique Keys
Symbols never collide. Private-ish. Perfect for metadata.
