Front-end developer and tech writer · View profile
· 4 min read
The Caesar cipher shifts every letter by a fixed amount. Learn how the shift works, why ROT13 is a special case, how to encode and decode by hand, and why the cipher offers no real security today.
· 4 min read
Convert calories to joules with the exact 4.184 factor, understand why food labels mix kcal and kJ, and read energy figures with confidence.
· 4 min read
Most adults read prose at about 200-250 words per minute. Learn what a normal reading speed is, how to measure yours in a minute, and why comprehension matters more than raw speed.
· 3 min read
Understand data units clearly: the 1024-vs-1000 split, bits versus bytes, and why a 1 TB drive shows as roughly 931 GB — with real file and storage sizes.
· 11 min read
Task lists are not in CommonMark. They are a GitHub Flavored Markdown extension, which is why the same file shows checkboxes in one place and literal brackets in another. The exact marker rule, what nesting does, and a table of what is CommonMark, what is GFM and what is neither — checked against both specs and four renderers.
· 3 min read
A URL slug is the readable, hyphenated part of a web address that names a page. Learn why slugs are lowercase, how they help SEO, and how to generate one from a title.
· 3 min read
Convert square feet to square meters and back with the exact factor 0.0929, worked room-size examples in both units, and why area factors are the square of length factors.
· 13 min read
"Break at spaces" fails in most of the world's writing systems. UAX #14 gives every character a line-break class; we looked ours up in Unicode 17.0.0 and ran a conforming implementation over no-break spaces, soft hyphens, zero-width spaces, URLs, Japanese and Thai.
· 13 min read
Turning a newline list into a comma list is trivial until an item contains a comma. RFC 4180's quoting rules, why a CSV field may contain a newline, why European spreadsheets use the semicolon, and what an empty item does to a round trip — every case run and printed.
· 14 min read
The nth most common word appears about 1/n as often as the first. We counted six public-domain books, printed rank × frequency, fitted log frequency against log rank, and got slopes between -1.02 and -1.08 in all six languages — plus the two places the law breaks.
· 3 min read
camelCase, snake_case, PascalCase, and kebab-case explained: what each looks like, where it is the convention, and how to choose one consistently.
· 3 min read
Convert milliliters to cups for cooking, with the key figure 1 US cup ≈ 237 mL, plus how the US cup, the metric cup, and the UK cup differ — and a ready-to-use table.
· 4 min read
A practical guide to turning a JSON array of objects into a clean CSV file, including how to flatten nested fields and handle the tricky edge cases.
· 3 min read
Convert miles per hour to kilometers per hour and back with the exact factor 1.609, common speed limits in both systems, and quick tricks you can do in your head.
· 12 min read
A link becomes text with its destination deleted, a nested list loses its hierarchy, a table becomes a row of words. Then the technical half: markdown has no single spec, and a regex stripper mangles a filename, a multiplication sign and the inside of a code block — all shown against a real parser.
· 12 min read
Case, whitespace, punctuation and diacritics: four policies, six real sentences, and the answer changes with each one. Then the harder half — reversing a string is itself undefined, and code-unit reversal breaks emoji and detaches accents, demonstrated in Node.
· 14 min read
Greedy against lazy on the same string, the dot that skips newlines, $& and $$ in the replacement, a reused /g regex that silently skips a row, and why /i knows nothing about Turkish i. Every failure run in Node, with a count-then-replace routine that catches them.
· 12 min read
Code-unit order, natural order and locale collation run on the same list in Node, with the outputs printed. Why Zebra beats apple, why item10 beats item9, and why ä sits next to a in German but after z in Swedish.
· 12 min read
The two directions fail in opposite ways. PNG to JPG silently flattens transparency onto a background colour the converter chooses — we got white from one tool and black from another on the same file. JPG to PNG recovers nothing and cost up to 11.4 times the bytes.
· 14 min read
A visible mark lives in the pixels, so it survives every copy — and degrades the image for every honest viewer at the same time. Measured: what a corner mark costs, what a tiled mark costs, and how each compares to metadata credit, Content Credentials and invisible watermarking.
· 13 min read
Five files cover every consumer that exists: the tab, the bookmark, the pinned tile, the Android home screen and the iOS home screen. The twenty-file lists are a dead browser matrix — with measurements showing what a 16-pixel icon can and cannot hold.
· 17 min read
Unix time counts seconds since 1970 while deliberately ignoring leap seconds, which is why it is not a count of elapsed physical seconds. Here is what that trade buys, what a leap second does to the counter, the exact instant a signed 32-bit counter overflows, and the factor-of-1000 bug that lands you in 1970 or the year 58589.
· 16 min read
Minification has to preserve meaning, and the interesting part is the whitespace that carries meaning: the descendant combinator, the spaces inside calc(), the gap between two inline elements. Measured here on real files, including how much brotli was going to save you anyway.
· 15 min read
A checksum catches accidents. A cryptographic hash resists an attacker. A hash-table hash spreads keys. Three different jobs, three different families — and here is a CRC-32 collision constructed by hand in 0.11 seconds to show exactly why you cannot substitute one for another.