MAP
Generated by scripts/gen-format-pages.py from docs/data/format-metadata/, FILE_FORMATS.csv and docs/formats-master.csv. Do not edit by hand: change the source, then run the script.
Source Map Preview.
At a glance
| Purpose | A JavaScript or CSS source map (version 3): JSON that maps a generated file back to its original sources. |
| Extensions | .map |
| Poka parser | poka-source-map |
| Viewer | poka-tree-viewer |
| Depth tier | Parser with a shared viewer (see Depth tiers) |
| Breadth tier | B4 Summary (see Breadth tiers) |
How much Poka reads
B4 Summary. The container and metadata are read and summarised (counts, properties, structure), but the main content is not rendered.
Confidence: medium (the reviewer read the code). Basis: Reviewed 2026-10-26: read parsers/poka-source-map/src/main.rs (354 lines, serde_json) and plugin.json; the three unit tests cover telling apart PCRaster and MapInfo .map files and broken JSON, not the source-map output. The corpus has node_webpack.js.map but no test reads it. Covers .map, .js.map and .css.map. The tree shows version, generated file, sourceRoot, the counts of sources and names, the size of the mappings string, whether sources are embedded, the ignore-list count and the number of indexed sections, and lists each source with whether its content is embedded. Judgement: B4, because the mappings, which are the content of the format, are measured but not decoded.
What Poka does not read
- The mappings (Base64 VLQ segments) are not decoded, so no position in the generated file can be traced to its source
- The names array is counted, not listed
- Embedded original sources (sourcesContent) are not shown
- Indexed maps: the sections are counted but not walked
- x_google_ignoreList is counted; which sources it marks is not shown
- Only the first 300 sources are listed
Libraries
Libraries Poka uses or has assessed for this format, with the status, licence and language the registry records.
- serde_json (used; MIT OR Apache-2.0; Rust)
- sourcemap (candidate; BSD-3-Clause; Rust; https://github.com/getsentry/rust-sourcemap) — Sentry's source map crate (9.3.2, Jan 2026); uses serde, loads the whole file into memory. Builds on serde_json, which Poka already uses.
- @jridgewell/trace-mapping (candidate; MIT; JavaScript/TypeScript; https://www.npmjs.com/package/@jridgewell/trace-mapping) — Traces original positions through a source map (0.3.31). Licence read from the registry's visible version entries.
- source-map (mozilla/source-map) (candidate; BSD-3-Clause; JavaScript; https://github.com/mozilla/source-map) — Generates and consumes source maps; npm 0.8.0.
- sourcemap (python-sourcemap) (candidate; licence unconfirmed; Python; https://github.com/mattrobenolt/python-sourcemap) — Parses JavaScript source maps; PyPI description says BSD but the licence field is blank. Last release Aug 2017.
Sources
- parsers/poka-source-map/src/main.rs
- parsers/poka-source-map/plugin.json