JS |模块化模式

Question

我在cacheDom函数中遇到$display，但是当我尝试在updateResult函数this.$display.text(temp).apply(this);中使用它时它不起作用。我认为这与范围规则有关，我肯定错过了一些东西。任何帮助将不胜感激。

$(document).ready(function() {
  (function() {
    var current = "", result = 0;
    var calculator = {
      init: function() {
        this.cacheDom();
        this.render();
        this.bindEvents();
      },
      cacheDom: function() {
        this.$button = $(".button p, .zero p");
        this.$display = $("#display p");
      },
      bindEvents: function() {
        this.$button.on("click", this.updateResult);
      },
      updateResult: function() {
        var temp = $(this).text();
        if (parseInt(temp) > 0 == false) {
          if (temp == "÷") {
            current += "/";
            this.$display.text(temp).apply(this);
          } else if (temp == "×") {
            current += "*";
            $("#display p").text(temp);
          } else if (temp == "-") {
            current += temp;
            $("#display p").text(temp);
          } else if (temp == "+") {
            current += temp;
            $("#display p").text(temp);
          } else if (temp == "=") {
            current = eval(current);
            $("#display p").text(current);
          } else if (temp == "C") {
            current = "";
            temp = "";
            result = 0;
            $("#display p").text(result);
          } else if (temp == "%") {
            current = current / 100;
            $("#display p").text(current);
          } else if (temp == "√") {
            $("#display p").text(Math.sqrt(parseInt(current[current.length - 1])));
            var sqrt = Math.sqrt(parseInt(current[current.length - 1]));
            current = current.substring(0, current.length - 1)
            current += sqrt;
          }
        } else {
          $("#display p").text(temp);
          current += temp;
        }
        console.log(current);
      },
      render: function() {

      },
    };
    calculator.init();
  })()
});