我一直坚持让这个计算器工作......所以基本上如果我按等于键，我的计算器就可以工作，（1 + 2 = 3）......但我想让它工作，即使用户只按运算符，比如1+4/5+2，这样即使只按运算符也会自动计算。
\n这是我的代码：
\n// DOM elements \nconst numberButton = document.querySelectorAll(\'.number\');\nconst operatorButton = document.querySelectorAll(\'.operator\');\nconst clearButton = document.querySelector(\'.clear\');\nconst deleteButton = document.querySelector(\'.delete\')\nconst showResult = document.querySelector(\'.result\');\nconst currentOperand = document.querySelector(\'.current-operand\');\nconst previousOperand = document.querySelector(\'.previous-operand\');\nconst equalsKey = document.querySelector(\'.equals-key\');\n\ncurrentOperand.textContent = \' \';\npreviousOperand.textContent = \' \';\n\n// Sum of a, b ... \nfunction add(a, b) {\n return a + b;\n};\n\n// Subtraction of a and b ...\nfunction subtract(a, b) {\n return a - b;\n};\n\n// Multiply a, b ... \nfunction multiply(a, b) {\n return a …