Function insertLeading

src/diff.js:1361–1367

(hunk, insert, their)

  }

  function insertLeading(hunk, insert, their) {
    while (insert.offset < their.offset && insert.index < insert.lines.length) {
      var line = insert.lines[insert.index++];
      hunk.lines.push(line);
      insert.offset++;
    }
  }

  function insertTrailing(hunk, insert) {
    while (insert.index < insert.lines.length) {