Question

Angular 7 TypeError：无法读取 setTitle 中未定义的属性“length”

2019-07-08

733

angular

我的 angular 项目上出现了一条神秘的错误消息 错误处理响应：TypeError：无法读取 setTitle 中未定义的属性“length”

错误消息导致此问题

content_script.js

function setTitle(result) {
    if(result[document.URL]) {
        document.title = result[document.URL];
    }
    else {
        var regex_list = result["regex"];
        for (i = 0; i < regex_list.length; i += 2) {
            if (document.URL.match(regex_list[i])) {
                document.title = regex_list[i+1];
            }
        }
    }
}

function onError(error) {
    console.log(`Error: ${error}`);
}

function init() {
    chrome.storage.sync.get(null, setTitle);
}

init();

我没有创建 content_script.js，我猜这是在构建项目时生成的

我的项目中唯一使用 setTitle 的地方是 app.component.ts

import { Component } from "@angular/core";
import { Title } from "@angular/platform-browser";

@Component({
  selector: "app-root",
  templateUrl: "./app.component.html",
  styleUrls: ["./app.component.css"]
})
export class AppComponent {
  title: string = "MY TITLE";

  public constructor(private titleService: Title) {}

  ngOnInit() {
    this.titleService.setTitle(this.title);
  }
}

如果我删除 ngOnInit 内容，错误仍然会出现

编辑： setTitle 导致此代码块

title.d.ts

/**
 * @license
 * Copyright Google Inc. All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.io/license
 */
/**
 * Factory to create Title service.
 */
export declare function createTitle(): Title;
/**
 * A service that can be used to get and set the title of a current HTML document.
 *
 * Since an Angular application can't be bootstrapped on the entire HTML document (`<html>` tag)
 * it is not possible to bind to the `text` property of the `HTMLTitleElement` elements
 * (representing the `<title>` tag). Instead, this service can be used to set and get the current
 * title value.
 *
 * @publicApi
 */
export declare class Title {
    private _doc;
    constructor(_doc: any);
    /**
     * Get the title of the current HTML document.
     */
    getTitle(): string;
    /**
     * Set the title of the current HTML document.
     * @param newTitle
     */
    setTitle(newTitle: string): void;
}

Answer 1

看起来你的数组是空的：

var regex_list = result["regex"];

尝试在运行循环语句之前添加数组检查：

var regex_list = result["regex"];
if (regex_list && regex_list.length) {
    for (i = 0; i < regex_list.length; i += 2) {
        if (document.URL.match(regex_list[i])) {
            document.title = regex_list[i+1];
        }
    }     
}

Answer 2

我遇到了同样的错误，当我从 Chrome 中删除 Chrome 扩展程序“重命名标签标题”后，该错误得到了解决

Answer 3

没关系，我的缓存只需要清除。这种错误不会再发生了，对不起大家

Thomas Fournet

2019-07-08