Chrome扩展:访问存储对象的数组的长度
Chrome扩展:访问存储对象的数组的长度
提问于 2018-09-06 06:56:42
我正在尝试访问存储objects的array的长度。当我将array打印到控制台时，当数组中只有一个object时，它只显示1，而当我尝试访问array的长度时，它显示undefined。
在弹出窗口中，我有一个文本字段，一旦输入文本并按下enter键，它就会将当前窗口中选项卡中的所有信息存储到storage中。信息存储在object中，object被添加到storage中的array中。然后，我根据array的长度在弹出窗口中创建按钮。
编辑：objectArr的类型为number，groupObject的类型为object。在我将groupObject推送到objectArr之前，我可以访问objectArr's length，推送之后我仍然可以访问objectArr's length。然而，当我实际更新objectArr时，objectArr变成了number。
background.js
chrome.runtime.onInstalled.addListener(onInstall);
/* runs on installation of extension */
function onInstall()
{
// objectArr will store the group objects
var objectArr = new Array();
chrome.storage.local.set({"objectArr": objectArr});
// initializes groupCount to 0
chrome.storage.local.set({"groupCount": 0});
}
function storeTabs(storeTabs)
{
chrome.storage.local.get(["groupCount", "objectArr"], function(group)
{
// current count of groups
var groupCount = group.groupCount;
var promptUser = storeTabs;
var groupObject = {};
/* stores all of the tab's information into an object and then puts object into storage */
chrome.tabs.query({currentWindow: true}, function(tabs)
{
/* gets each tab's name and url from an array of tabs and stores them into arrays */
var tabNamesArr = [];
var tabUrlsArr = [];
var tabCount = 0;
for (; tabCount < tabs.length; tabCount++)
{
tabNamesArr[tabCount] = tabs[tabCount].title;
tabUrlsArr[tabCount] = tabs[tabCount].url;
}
/* initialize object content */
var groupName = "groupName" + groupCount;
groupObject[groupName] = promptUser;
var tabNames = "tabNames" + groupCount;
groupObject[tabNames] = tabNamesArr;
var tabUrls = "tabUrls" + groupCount;
groupObject[tabUrls] = tabUrlsArr;
console.log("before push, group.objectArr.length: " + group.objectArr.length);
var objectArr = group.objectArr.push(groupObject);
console.log("after push, group.objectArr.length: " + group.objectArr.length);
console.log("typeof group.objectArr: " + typeof group.objectArr);
console.log("typeof group.objectArr.push(groupObject): " + typeof objectArr);
// updates storage with new objectArr with groupObject
chrome.storage.local.set({"objectArr": objectArr});
/* prints everything in storage */
chrome.storage.local.get(null, function(items)
{
var allKeys = Object.keys(items);
console.log("storage: " + allKeys);
})
/* prints objectArr and objectArr.length */
chrome.storage.local.get("objectArr", function(group)
{
console.log("objectArr: " + group.objectArr);
console.log("objectArr.length: " + group.objectArr.length);
})
// set-up for next group so last group isn't overwritten
chrome.storage.local.set({"groupCount": (groupCount + 1)});
})
}
}popup.js
document.addEventListener("DOMContentLoaded", function()
{
var storeTabs = document.getElementById("storeTabs");
storeTabs.addEventListener("keyup", function(enterKey)
{
if (enterKey.keyCode == 13)
{
// get text from text field
var storeTabs = document.getElementById("storeTabs").value;
chrome.extension.getBackgroundPage().storeTabs(storeTabs);
}
})
}
displayButtons();
/* Display buttons for popup */
function displayButtons()
{
chrome.storage.local.get("objectArr", function(group)
{
var objectArr = group.objectArr;
console.log("objectArr: " + group.objectArr);
console.log("objectArr.length: " + objectArr.length);
for (var i = 0; i < objectArr.length; i++)
{
getStorage(i);
}
})
}后台脚本控制台
before push, group.objectArr.length: 0
after push, group.objectArr.length: 1
typeof group.objectArr: object
typeof group.objectArr.push(groupObject): number
storage: groupCount,objectArr
objectArr: 1
objectArr.length: undefined弹出脚本控制台
objectArr: 1
objectArr.length: undefined回答 1
Stack Overflow用户
回答已采纳
发布于 2018-09-06 08:43:05
我认为这是错误的。
console.log("before push, group.objectArr.length: " + group.objectArr.length);
// var objectArr = group.objectArr.push(groupObject); assinged 1...
group.objectArr.push(groupObject);
var objectArr = group.objectArr;
console.log("after push, group.objectArr.length: " + group.objectArr.length);
console.log("typeof group.objectArr: " + typeof group.objectArr);
console.log("typeof group.objectArr.push(groupObject): " + typeof objectArr);页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/52194378
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