bracketsLint.js

const tests = {
  valid: '{[(())]}',
  valid2: '{}',
  valid3: '()',
  valid4: '[]',
  valid5: '{[]}',
  valid6: '{[()]}',
  valid7: '',
  valid8: '[]{}[][]()()',
  invalid0: '[{}]',
  invalid1: ']})',
  invalid2: '[{]}',
  invalid3: '{[(',
  invalid4: '((({{{}}})))',
  invalid5: '[{()}]',
}

const BRACKETS_LIST = {
  '{': '}',
  '[': ']',
  '(': ')',
}

const OPENING_BRACKETS_LIST = Object.keys(BRACKETS_LIST).join('')

const isOpeningBrackets = (item) => OPENING_BRACKETS_LIST.includes(item)

const isCorrectOrder = (first, second) => {
  if (first === false) {
    return true
  }

  const isValidItems =
    OPENING_BRACKETS_LIST.includes(first) &&
    OPENING_BRACKETS_LIST.includes(second)

  const isValidOrder =
    OPENING_BRACKETS_LIST.indexOf(first) <=
    OPENING_BRACKETS_LIST.indexOf(second)

  return isValidItems && isValidOrder
}

const isCorrectClosingItem = (opening, closing) =>
  BRACKETS_LIST[opening] === closing

function isValidBrackets(input) {
  const stack = []

  let isValid = true

  for (let cursor = 0; isValid && cursor < input.length; cursor++) {
    const currentItem = input[cursor]
    const topItemInStack = stack[stack.length - 1] || false

    if (isOpeningBrackets(currentItem)) {
      if (isCorrectOrder(topItemInStack, currentItem)) {
        stack.push(currentItem)
      } else {
        isValid = false
      }
    } else if (isCorrectClosingItem(topItemInStack, currentItem)) {
      stack.length = stack.length - 1
    } else {
      isValid = false
    }
  }

  if (stack.length > 0) {
    isValid = false
  }

  return isValid
}

Object.keys(tests).map((key) =>
  console.log(
    `Testing ${key} - ${tests[key]} ::: ${isValidBrackets(tests[key])}`
  )
)