@livefolio/sdk / applyFills

Function: applyFills()

applyFills(portfolio, fills, orders): Portfolio

Defined in: portfolio/apply.ts:54

Applies a batch of confirmed fills to a portfolio, returning a new Portfolio snapshot. This is the single function that advances portfolio state after order execution.

For each fill the corresponding order is looked up in orders by fill.orderRef. The order's kind determines the accounting treatment:

• 'open' — adds a new Position and debits cash.
• 'close' — removes shares from an existing position and credits cash.
• 'adjust' — updates the position's quantity; only fees are debited.
• 'rebalance' — buys or sells shares in the long position for asset; creates or removes the position as needed.

The returned portfolio.t is updated to the maximum fill timestamp.

Parameters

Parameter	Type	Description
portfolio	Portfolio	The current portfolio state before this batch.
fills	readonly Fill[]	Execution confirmations returned by Executor.submit. Each fill's orderRef MUST match an id in orders.
orders	readonly Order[]	The full order batch that was submitted. Used to look up order details for each fill.

Returns

Portfolio

A new Portfolio with updated positions, cash, and timestamp. The input portfolio is not mutated.

Example

import { applyFills } from '@livefolio/sdk';
import type { Portfolio, Order, Fill } from '@livefolio/sdk';

const portfolio: Portfolio = { cash: 10_000, positions: [], t: new Date('2024-01-01') };

const order: Order = {
  id: 'ord_1', kind: 'open',
  asset: { kind: 'equity', id: 'AAPL', symbol: 'AAPL' },
  side: 'long', quantity: 10,
};
const fill: Fill = { orderRef: 'ord_1', t: new Date('2024-01-02'), quantity: 10, price: 185, fees: 0 };

const next = applyFills(portfolio, [fill], [order]);
// next.cash === 8_250, next.positions.length === 1