transform

function Delta.transform<T>(
  a: Delta<T>,
  b: Delta<T>,
  priority?: boolean,
): Delta<T>

Transforms delta b to account for delta a having been applied first. When both deltas insert at the same position, priority determines which insert comes first.

Example

data-first

import { Delta } from "@monstermann/delta";

const a = Delta.insert([], "Hello");
const b = Delta.insert([], "World");

Delta.transform(a, b, true);
// [{ type: "retain", value: 5 },
//  { type: "insert", value: "World" }]

Delta.transform(a, b, false);
// [{ type: "insert", value: "World" }]

const format = Delta.retain([], 5, { bold: true });
const insert = pipe(
    [],
    Delta.retain(2),
    Delta.insert("XXX")
);

Delta.transform(insert, format);
// [{ type: "retain", value: 8, attributes: { bold: true } }]

data-last

import { Delta } from "@monstermann/delta";

const a = Delta.insert([], "Hello");
const b = Delta.insert([], "World");

pipe(a, Delta.transform(b, true));
// [{ type: "retain", value: 5 },
//  { type: "insert", value: "World" }]