Error codes

Every error bo-grid throws has a stable code, says what went wrong with the value it got, gives the exact fix, and links here.

An error from bo-grid reads like this:

BG2004: TradeTape: capacity must be a number of 1 or more, got 0. Fix: Pass how many trades to keep, e.g. new TradeTape(500). See https://bonguynvan.github.io/bo-grid/docs/errors/#bg2004

• The code (BG2004) never changes meaning, so you can search for it, test for it, and match it in error reporting. It is also on the error as error.code.
• The message says what happened, with the value the grid got.
• The fix says exactly what to change.
• The link opens the code’s entry on this page.

The error is still an Error, TypeError, RangeError or SyntaxError, so existing catch blocks keep working. Its type is exported as BoGridError:

import type { BoGridError } from 'bo-grid';
import { createPositions, type PositionFill } from 'bo-grid/trading';

const positions = createPositions();

function record(fill: PositionFill) {
  try {
    positions.fill(fill);
  } catch (e) {
    if ((e as BoGridError).code === 'BG3003') showQtyHint();
    else throw e;
  }
}

A coding agent that hits one of these errors can follow the fix as written, without reading the library’s source.

Grid

BG1001

hotkeys: a binding has no key, as in 'Ctrl+'. End the binding with a key: 'Ctrl+B', 'Delete' or '+'. See Keyboard & hotkeys.

BG1002

hotkeys: an unknown modifier, as in 'Ctl+B'. Use Shift, Alt, Ctrl, Meta or Mod (Ctrl or ⌘, whichever is pressed), joined with +.

BG1003

hotkeys: a Shift binding that cannot fire, as in 'Shift+1'. A key event reports the character Shift types, not the key under it, so bind that character: '!' for Shift+1, '?' for Shift+/.

BG1004

hotkeys: a key bound twice, as in { b: …, B: … }, or Mod+K next to Ctrl+K (Mod+K binds both Ctrl+K and Meta+K). Give each key one binding.

BG1101

parseJSON: the text is not a JSON array of objects. Pass text like [{"id":1,"sym":"AAA"}]; wrap a single object in [ ]. See Export & import.

BG1102

exportXLSX: the optional peer dependency xlsx is not installed. Install it next to bo-grid: npm i xlsx. The core never loads it until you export.

BG1103

parseJSON: the text is not valid JSON. The message includes the parser’s reason. Pass the JSON text as received; for CSV or TSV text use parseCSV or parseTSV, or parseRows to detect the format. A SyntaxError, as before.

BG1201

Sparkline: no 2d canvas context. Sparklines draw on a canvas, which a test environment such as jsdom does not have. Draw them in a browser; in tests, stub HTMLCanvasElement.prototype.getContext.

Realtime

BG2001

serveFeed: a feed with that name already runs in this worker. Give each feed in a worker its own name, or close the first one. See Worker feeds.

BG2002

createOrderBook: maxLevels is not a whole number above 0. Pass a whole number, such as maxLevels: 20, or leave it out to keep every level. See Order book.

BG2003

createLinger: ms is not a finite number of 0 or more. Pass how long a row lingers, in milliseconds, such as ms: 3000 (0 removes it at once). See Orders & positions.

BG2004

TradeTape: the capacity is below 1 or not a finite number. Pass how many trades to keep, such as new TradeTape(500); a fraction is rounded down. See Depth ladder.

Trading

BG3001

createPositions: a fill’s symbol is empty or not a string. Pass the instrument’s symbol: { symbol: 'VNM', side: 'buy', qty: 100, price: 68.5 }. See Orders & positions.

BG3002

createPositions: a fill’s side is not 'buy' or 'sell'. Pass side: 'buy' or side: 'sell', in lower case.

BG3003

createPositions: a fill’s qty is not a number above 0. Pass the filled quantity as a positive number; the side says which way (side: 'sell', not a negative qty).

BG3004

createPositions: a fill’s price is not a finite number. Pass the price as a number, such as price: 68.5; parse strings first.

BG3005

createPositions: a fill’s fee is not a finite number. Pass the fee as a number, such as fee: 1.2, or leave it out.