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Showing content from https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Errors/Cant_delete below:

TypeError: property "x" is non-configurable and can't be deleted - JavaScript

TypeError: property "x" is non-configurable and can't be deleted 消息 
TypeError: property "x" is non-configurable and can't be deleted. (Firefox)
TypeError: Cannot delete property 'x' of #<Object> (Chrome)
错误类型

TypeError 只出现在严格模式下。

哪里有问题？

尝试删除某个属性，但是这个属性是不可配置的。configurable 属性控制是否该属性能从对象上删除，以及它的属性（除了writable）能否被修改。

这个错误仅仅在严格模式下出现。在非严格模式下，这个操作返回 false。

示例

不可配置的属性并不特别常见，但是它们可以使用 Object.defineProperty() 或 Object.freeze() 创建。

"use strict";
var obj = Object.freeze({ name: "Elsa", score: 157 });
delete obj.score; // TypeError

("use strict");
var obj = {};
Object.defineProperty(obj, "foo", { value: 2, configurable: false });
delete obj.foo; // TypeError

("use strict");
var frozenArray = Object.freeze([0, 1, 2]);
frozenArray.pop(); // TypeError

也有一些内建于 JavaScript 的不可配置属性。你可能会尝试删除一个数学常量。

"use strict";
delete Math.PI; // TypeError
参见

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