@mpt/line-map

Convert between lines/columns and offsets.

Why?

• Has a one-to-one mapping between positions and offsets:
  • For every position there is exactly one offset and vice versa.
  • Converting positions and offsets that do not exist will return undefined.
• Position objects are compatible with vscode's extension api.
• Can be used to find all line start offsets in a string.
• Supports custom line separators.
  • By default \n is used, which will also work with \r\n.
• Conversions using an existing line map are very fast:
  • Converting position to offset has a complexity of O(1).
  • Converting offset to position has a time complexity of O(log n) where n is the number of lines.
• Exports both CommonJS and ES modules.

Usage

import { LineMap } from "@mpt/line-map";

const map = new LineMap("\n  Hello World!\n");

map.getPosition(4);
// => { line: 1, character: 1 }

map.getOffset({ line: 1, character: 1 });
// => 4

map.offsets
// => [0, 1, 16]

map.text
// => "\n  Hello World!\n"