error: Each LinearRing of a Polygon must have 4 or more Positions

[Stefan Siegl]

If the bbox of overpass-layer changes just in its width (i.e. southern and northern edge remaining exactly the same), then the following error occurs in @turf/difference (version 6.0.2 as set in the lock file, and included in dist version)

Uncaught Error: Each LinearRing of a Polygon must have 4 or more Positions.
    at Object.polygon (overpass-layer.js:3354)
    at Object.difference (overpass-layer.js:3027)
    at KnownArea.check (overpass-layer.js:35693)
    at RequestBBox.needLoad (overpass-layer.js:34479)
    at RequestBBox.mayFinish (overpass-layer.js:34483)
    at overpass-layer.js:32280
    at Array.forEach (<anonymous>)
    at OverpassFrontend._overpassProcess (overpass-layer.js:32275)
    at OverpassFrontend.<anonymous> (overpass-layer.js:32605)
    at overpass-layer.js:23185

KnownArea.check calls difference with two bbox'es, and in this special constellation it fails. Minimal demo script:

const difference = require("@turf/difference")

const a = {"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[9.95908498764038,49.7960939701678],[9.978911876678467,49.7960939701678],[9.978911876678467,49.79909957355378],[9.95908498764038,49.79909957355378],[9.95908498764038,49.7960939701678]]]}}
const b = {"type":"Feature","properties":{},"geometry":{"type":"Polygon","coordinates":[[[9.96085524559021,49.7960939701678],[9.977141618728638,49.7960939701678],[9.977141618728638,49.79909957355378],[9.96085524559021,49.79909957355378],[9.96085524559021,49.7960939701678]]]}}

console.log(difference(a, b));

This can also be reproduced with the overpass-layer demos, by e.g. opening the browser console to the right of the layer and then shrink the console after initial loading has completed.

The latest version of @turf/difference (6.3.0) has this fixed already, hence it'd suffice to simply update this dependency and rebuild.

[Stephan Bösch-Plepelits]

Does not happen in the current version any more.