Grid Shift

AxisSplice

_interface

One structural edit to an axis: count lines removed at the 1-based start, with everything after the removed span moved by delta. delta is the net movement, so a pure insert of two lines is {count: 0, delta: 2} and a pure delete of three is {count: 3, delta: -3}.

The four travel as one value because they describe one edit, and because three of them are number: passed positionally, two adjacent ones transposed compiles, typechecks, lints, and moves a merge, a dropdown, a highlight or a comment anchor onto cells the author never chose -- silently, since nothing about the resulting file is malformed. A named field cannot be transposed.

interface AxisSplice {
  /** The axis the lines were spliced on. */
  readonly axis: 'row' | 'col';
  /** 1-based first line of the removed span. */
  readonly start: number;
  /** How many lines were removed. */
  readonly count: number;
  /** Net movement of every line after the removed span. */
  readonly delta: number;
}