Valid Braces kata published in codewars

validBraces.coffee

validBraces = (braces) ->
  bracesMap = {
    ']': '[',
    ')': '(',
    '}': '{'
  }
    
  stack = [];
  for i in [0...braces.length]
    if braces[i] in ['(', '{', '['] then stack.push braces[i]  
    if braces[i] in [')','}', ']']
      openBrace = bracesMap[braces[i]]
      if stack[stack.length - 1] isnt openBrace then return false
      else stack.pop()   
  return stack.length is 0