How to fake a near-miss

The minimum code

function nearMissGrid(reelCount: number, visibleRows: number, scatter: string, nearReel: number, count: number) {
  // fill random, then sprinkle count-1 scatters on NOT-nearReel, then wipe any on nearReel
  const grid: string[][] = /* random fill */;
  const coords = /* all coords NOT on nearReel, shuffled */;
  for (let i = 0; i < count - 1; i++) {
    const [r, row] = coords[i];
    grid[r][row] = scatter;
  }
  for (let row = 0; row < visibleRows; row++) {
    if (grid[nearReel][row] === scatter) grid[nearReel][row] = pickNonScatter();
  }
  return grid;
}

const promise = reelSet.spin();
setTimeout(() => {
  reelSet.setAnticipation([nearReelIndex]);
  reelSet.setResult(nearMissGrid(5, 3, 'scatter', 4, 3));
}, 200);

Or — use the cheat

The same logic ships in the cheats library as forceNearMiss(count, symbolId, nearReelIndex):

import { forceNearMiss } from '@/shared/cheats';

engine.register({
  id: 'near-miss-r5',
  label: 'Near-miss on reel 5',
  enabled: true,
  cheat: forceNearMiss(3, 'scatter', 4),
});

Why this works

Near-miss sits between two reward systems in the player’s head: the immediate reward of a visible pattern, and the anticipated reward of a trigger. Anticipation holds the final reel long enough for both systems to fire. The grid always resolves to a loss — but the timing convinces the player that winning was within reach.