booleanIntersects unpredictable, given two line segments sharing an endpoint

[bblack]

turf 6.5.0

var turf = require("@turf/turf");

// Two line segments that share the same start point:
var a = [
  [ -64.4522672777778, 53.738182155555506 ],
  [ -64.45201727777784, 53.7386266 ]
];
var b = [
  [ -64.4522672777778, 53.738182155555506 ],
  [ -64.45223950000003, 53.738182155555506 ]
];

turf.booleanIntersects(
  turf.lineString(a), turf.lineString(b)
); // true
turf.booleanIntersects(
  turf.lineString(a), turf.lineString(b.toReversed())
); // true
turf.booleanIntersects(
  turf.lineString(a.toReversed()), turf.lineString(b)
); // true
turf.booleanIntersects(
  turf.lineString(a.toReversed()), turf.lineString(b.toReversed())
); // false

[smallsaucepan]

Hi @bblack. Would you mind trying this with one of the available Turf alphas? For example 7.0.0-alpha.2

I tried to reproduce this locally and all four returned true. If a newer version of Turf doesn't help, something else to try is I used a.splice().reverse() rather than a.toReversed() to get a reversed copy of the array.

Let us know what you find, and we can dig further if those don't work.

[bblack]

@smallsaucepan : i tried my example on 7.0.0-alpha.2 , and the issue does not occur there: all four cases return "true", including the last one which was returning "false" on 6.5.0.