You Don't Know JS
The recorded URL now redirects offsite — often an acquisition, rebrand, or wind-down; the destination is recorded in the telemetry below. Pulse has been flat over the last 30 days. Observation is liveness-only: no tracked press, repository, or traffic rank — existence is confirmed, momentum is unobserved.
HTTP liveness
realSignal telemetry
4 families · 1 observed · observed onlyamazon.comedge
direct originserver
ServerTranco rank
unranked
Analyst read
generated from the observed metrics above · no external narrativeYou Don't Know JS's listed URL redirected off its original domain (to https://www.amazon.com/gp/product/1491904240/ref=as_li_ss_tl?ie=UTF8&linkCode=sl1&tag=krux-20&linkId=b20460e92b45bc0517bffe3cbd919646) when we last probed it on Aug 24, 2026 — we mark it redirected, not dead. It has fewer than two observed signal families, so no Pulse Index is composed — the evidence strip shows what is and isn’t present. Observed footprint: 4 functional tags. It has no curated competitive-alternative edges yet, so the comparable set below is functional tag-similarity — read it with the confidence flags.
Comparable set
curated alternatives → functional tag-similarity| Company | Basis | Overlap | Pulse | 30d Δ | Status |
|---|---|---|---|---|---|
| Grokking the Java Intervieweducation | similar | 100% | 40.0 | 0.0 | ● live |
| Laws of UX (The Book)education | similar | 80% | 40.0 | 0.0 | ● live |
| The Art of R Programming:dev-tools | tag-overlap | 80% | 16.0 | 0.0 | → redirected |
| Introduction to Algorithmseducation | similar | 80% | 40.0 | +9.6 | ● live |
| Hello Web Designeducation | similar | 80% | 40.0 | 0.0 | ● live |
| Machines of Loving Graceeducation | similar | 80% | 40.0 | +7.2 | ● live |
| Web Interface handbookeducation | similar | 80% | 44.0 | 0.0 | ● live |
| The Official Ubuntu Bookeducation | similar | 80% | 16.0 | 0.0 | → redirected |
Confidence reflects source and category coherence: curated = an editorially linked alternative; similar = strong functional tag-overlap in the same category; tag-overlap = shared tags only and may be noisy. Overlap is the shared functional-tag ratio (Jaccard) for tag-matched rows. Pulse is the observed-activity index real and 30d Δ its signed month change; a dash means insufficient observed history, never zero.
Structure
observed attributesFunding & team
not in sourceNo disclosed funding in our sources. Funding data covers only ~1% of the corpus (462 rounds across 79K products), so absence here is unknown, not zero— we don't estimate a number we can't source.