date-threshold-arithmetic skillA
date-threshold-arithmetic is agent-read markdown (skill) from fabioc-aloha/alex_skill_mall: Date comparisons at thresholds fail due to fractional days:.
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
# Date Threshold Arithmetic
## The Problem
Date comparisons at thresholds fail due to fractional days:
```javascript
const daysBetween = (Date.now() - someDate.getTime()) / (1000 * 60 * 60 * 24);
// someDate is "exactly 7 days ago"
// daysBetween = 7.000012 (due to milliseconds)
// if (daysBetween > 7) { ... } // TRUE — unexpected!
```
## The Solution
Always `Math.floor()` before threshold comparison.
```javascript
function daysSince(date) {
const ms = Date.now() - new Date(date).getTime();
return Math.floor(ms / (1000 * 60 * 60 * 24));
}
// Now "exactly 7 days" = 7, not 7.000012
if (daysSince(lastCheck) > 7) {
// Truly more than 7 full days
}
```
## Common Traps
| Code | Bug |
|------|-----|
| `days > 7` | Triggers on 7.0001 |
| `days >= 7` | Doesn't trigger on 6.9999 |
| `days === 7` | Never true for fractional values |
## Safe Patterns
```javascript
// Days since (full days only)
const fullDays = Math.floor((now - then) / MS_PER_DAY);
// Is it past the threshold?
if (fullDays > threshold) { ... }
// Is it on or past the threshold?
if (fullDays >= threshold) { ... }
// Is it exactly N days?
if (fullDays === threshold) { ... }
```
## For Cron-Style Checks
…Read the whole file at its exact version.
How to install
mdr add fabioc-aloha/alex_skill_mall/date-threshold-arithmetic@git:20260728.80a7ab6mdr add fabioc-aloha/alex_skill_mall/date-threshold-arithmetic@sha256:d5e7c685dca8fd16Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_tp6chzpw5huh2gy3)
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Versions
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (1983 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
fabioc-aloha/alex_skill_mall · 4 stars · license MIT · pushed 2026-09-21 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_tp6chzpw5huh2gy3 GET https://markdownregistry.com/api/v1/resolve?ref=fabioc-aloha/alex_skill_mall/date-threshold-arithmetic GET https://markdownregistry.com/api/v1/blob/d5e7c685dca8fd162f36ceadd16d0be7c4cd137c7fe12c705c55eeedb30fdd9a
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