I Built Minesweeper in ~50 Lines — the Only Hard Part Is Flood-Fill

Minesweeper feels intricate — numbers, cascading reveals, flags. Build it and you find it's a grid, a neighbour count, and one recursive function . This is Day 6 of my GameFromZero series. Each cell holds four facts const cell = { mine : false , open : false , flag : false , n : 0 }; n = how many of the 8 neighbours are mines. That number is all the player gets to reason about. Count neighbours once After scattering mines randomly, precompute every non-mine cell's n : let n = 0 ; neighbours ( r , c , ( rr , cc ) => { if ( cells [ rr ][ cc ]. mine ) n ++ ; }); cell . n = n ; Flood-fill is the whole trick When you open a cell with zero neighbouring mines, there's nothing dangerous nearby — so auto-open all 8 neighbours, and if any of those are also zero, they cascade. That's why one click can clear half the board. It's recursion: function open ( r , c ) { const cell = cells [ r ][ c ]; if ( cell . open || cell . flag ) return ; // base case cell . open = true ; if ( cell . n === 0 ) neighbours ( r , c , ( rr , cc ) => open ( rr , cc )); // recurse } This is the same algorithm behind the paint-bucket tool and maze region-filling. Flags + win/lose Right-click toggles a flag (and blocks accidental opens). Click a mine → lose. Win when opened cells = total − mines: if ( cell . mine ) gameOver (); if ( opened === R * C - M ) win (); That's the entire game. Master the state-step-draw loop once and every classic — Snake, Pong, Tetris, 2048, Minesweeper — is an evening each. ▶️ Play it + read the step-by-step breakdown: https://dev48v.infy.uk/game/day6-minesweeper.html Day 6 of GameFromZero.