function bracketsMaxDepth(str) { const obj = { ")": '(', "}": '{', "]": '[' } let stack = [] let depth = 0 for (let s of str) { if (obj[s]) { if (stack.pop() != obj[s]) { return 0 } } else { stack.push(s) depth = Math.max(depth,stack.length) } } return stack.length == 0 ? depth : 0 }