Error message:Cannot read property get of undefined

这个错误消息 "Error message: Cannot read property 'get' of undefined" 出现通常是因为JavaScript试图访问一个未定义的对象的属性。`get` 是 JavaScript 中对象属性访问的一种常见语法，比如 `obj.get()`。当你尝试从 `undefined` 对象上调用 `get` 时，因为该对象还未初始化或不存在，所以会抛出这个错误。

例如：

let obj;
console.log(obj.get()); // 抛出 "TypeError: Cannot read property 'get' of undefined"

要解决这个问题，你需要检查代码逻辑，确保在尝试访问 `get` 属性之前，`obj` 已经被赋予了一个有效的值，或者提供一个默认值或者错误处理机制来避免这种异常：

let obj = {};
if (obj && typeof obj.get === 'function') {
    obj.get();
} else {
    console.error('obj is undefined or does not have a get method');
}

相关问题

TypeError: Cannot read properties of undefined (reading 'num')" found in

This error message typically occurs when you try to access a property or method of an undefined variable.

For example, if you have the following code:

let obj;
console.log(obj.num);

You will get the "TypeError: Cannot read properties of undefined (reading 'num')" error because the `obj` variable is undefined and does not have a `num` property.

To fix this error, you need to make sure that the variable you are trying to access is defined and has the property or method you are trying to use. You can do this by checking if the variable is not undefined before accessing its properties or methods. For example:

let obj = { num: 42 };
if (obj !== undefined) {
  console.log(obj.num);
}

This code will only try to access the `num` property if `obj` is defined, preventing the error from occurring.

Cannot read property 'querySelector' of undefined

This error message usually appears when you try to call the `querySelector` method on a variable that is undefined.

For example, if you have a variable `element` that you expect to reference a DOM element, but it is not properly initialized or assigned, then when you try to call `element.querySelector()`, you'll get the "Cannot read property 'querySelector' of undefined" error.

To fix this error, make sure that your variables are properly initialized or assigned before attempting to call methods on them. You may also want to check if the element you're trying to query actually exists on the page.