dates-le

Find every date and timestamp in a codebase, and the instant each one resolves to.

A date is the one literal that looks correct in review and is wrong in production. 2024-01-15 in a config, 1705276800 in a fixture and Mon, 15 Jan 2024 10:30:45 GMT in a test are the same instant written three ways, and no reviewer holds all three in their head. "What dates are hardcoded in here, and which have already passed" is not a question grep can answer, because grep matches text and the question is about time.

cargo install dates-le

dates-le src/                       # every date, as JSON, one line per file
dates-le --before 2026-01-01 .      # everything already in the past
dates-le --sort --iso config/       # ordered by instant, in readable form
dates-le --values . | sort -u       # just the strings, for piping

Exit codes follow grep: 0 dates found, 1 none found, 2 a malformed question. Finding none is an answer, not an error.

A file that is not text, or that cannot be opened, is named on stderr and carried in the report rather than failing the run — every repository has a PNG in it. --strict turns those back into a failure.

What it reads

JSON, YAML, CSV, XML, log and plaintext, JavaScript, TypeScript and HTML. There is no parsing — every format is the same scan over raw text, and the format only decides which extra patterns join the six shared ones. A malformed document still yields its dates.

XML comments are skipped. Log files add syslog and Apache access lines. JavaScript and TypeScript add date-constructor arguments, which is how a string like March 5, 2024 — recognisable only by where it sits — is found at all.

The instant is the point

Every value carries the epoch-millisecond instant it resolves to, and a value whose instant cannot be resolved is not reported. That gate is what keeps a phone number out of the output.

Resolution matches Date.parse in V8 exactly, including the legacy parser no standard describes: garbage words are legal before the first number and fatal after it, weekday names are read and discarded, months match on three letters, EST is a fixed −5 rather than a zone, and a two-digit year is 1900s from 50. Those rules were established by asking V8 and are pinned in fixtures/date-parse.json, which cargo test replays.

A date with no timezone resolves against this machine's. Four of the six shapes carry no zone, so their instant genuinely differs by machine — exactly as it does for the code being audited. --tz UTC names one instead, and applies to --after and --before too, so where the command was typed cannot change the answer. At a daylight-saving transition the offset in force before the transition wins, for both the hour that does not exist and the hour that happens twice.

As an MCP server

dates-le mcp

Two tools. extract_dates takes document text and is byte-identical to the one the VS Code extension's server offers — the same corpus runs against both. dates_le_scan reads files and directories.

The other half

This is the CLI and MCP half of dates-le, a VS Code extension. Extraction is shared and held identical by fixtures/; the extension's converting, filtering and validating are interactive and stay in the editor. SPEC.md is the behavioural contract, divergences included.

MIT.