Error in render: "TypeError: Cannot read properties of undefined (reading '2')"

在Vue.js中，当出现"TypeError: Cannot read properties of undefined (reading 'length')"错误时，这通常意味着你在模板中访问了一个未定义或空值的属性。 例如，在你的代码中，出现了类似于"TypeError: Cannot read properties of undefined (reading '2')"的错误。

为了解决这个问题，你可以在访问属性之前添加一级判断，检查该属性是否已定义。 在你的例子中，你可以使用类似的方式检查`monthCourseHours`是否已定义，然后再访问其属性。例如：

{{ totalCourseHours !== undefined && monthCourseHours !== undefined && monthCourseHours.length > 0 ? monthCourseHours : 0}}

这样，如果`monthCourseHours`未定义或为空，你将不会再遇到"TypeError"错误。你可以根据实际情况调整判断条件和操作。<span class="em">1</span><span class="em">2</span><span class="em">3</span>
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