if (modifiedStart <= modifiedEnd) {
Debug.Assert(originalStart === originalEnd + 1, 'originalStart should only be one more than originalEnd');
diff.ts
// All insertions
changes = [
new DiffChange(originalStart, 0, modifiedStart, modifiedEnd - modifiedStart + 1)
];
} else if (originalStart <= originalEnd) {
Debug.Assert(modifiedStart === modifiedEnd + 1, 'modifiedStart should only be one more than modifiedEnd');