第一次部署Chrome Extension- undureck typeError:无法读取NULL的属性(读取'长度')
我正在尝试部署我的第一个JavaScript应用程序,这是Chrome扩展名。 这只是生成随机密码,并使用当前活动选项卡的URL存储。
应用程序在本地运行良好,但是将其部署到Chrome之后,我得到了此错误:
unturew typeerror:无法读取空的属性(读取“长度”) index.js:65(匿名函数)
我是初学者,因此对我的代码的任何批评都得到了高度赞赏。 太感谢了。
function render() {
*line65* **if(passwords.length === 0)** {
document.getElementById("saved-passwords-container").style.display= "none";
} else {
document.getElementById("saved-passwords-container").style.display= "unset";
}
let list = ""
**for (let i = 0; i < passwords.length; i++)** {
list += `<div class="saved-password-line"><span>${passwords[i]}</span></br></br><span class="link"><a target='_blank'href='${links[i]}'>${links[i]}</a></span></div>`
}
document.getElementById("passwords-el").innerHTML = list
}
这是完整的index.js文件:
var characters = [];
for (var i=32; i<127; i++)
characters.push(String.fromCharCode(i));
for( var i = 0; i < characters.length; i++){
if ( characters[i] === '<') {
characters.splice(i, 1);
i--;
}
}
for( var i = 0; i < characters.length; i++){
if ( characters[i] === '>') {
characters.splice(i, 1);
i--;
}
}
let pw1El = document.getElementById("pw1-el")
let pw1 = ""
let passwords = []
passwords = JSON.parse(localStorage.getItem("savedPasswords"))
let links = []
links = JSON.parse(localStorage.getItem("savedLinks"))
render()
document.getElementById("char-count-el").value = 20
document.getElementById("gen-btn").addEventListener("click", function() {
var charCount = document.getElementById("char-count-el").value
pw1 = ""
for(let i = 0; i < charCount; i++) {
let randomIndex = Math.floor(Math.random() * characters.length)
pw1 += (characters[randomIndex])
}
pw1El.textContent = pw1
})
document.getElementById("save-btn").addEventListener("click", function() {
passwords.push(pw1El.innerText)
chrome.tabs.query({active: true, currentWindow: true}, function(tabs){
links.push(tabs[0].url)
})
localStorage.setItem("savedPasswords", JSON.stringify(passwords))
localStorage.setItem("savedLinks", JSON.stringify(links))
render()
})
function render() {
**if(passwords.length === 0)** {
document.getElementById("saved-passwords-container").style.display= "none";
} else {
document.getElementById("saved-passwords-container").style.display= "unset";
}
let list = ""
**for (let i = 0; i < passwords.length; i++)** {
list += `<div class="saved-password-line"><span>${passwords[i]}</span></br></br><span class="link"><a target='_blank'href='${links[i]}'>${links[i]}</a></span></div>`
}
document.getElementById("passwords-el").innerHTML = list
}
document.getElementById("clear-btn").addEventListener("click", function() {
passwords = []
links = []
localStorage.setItem("savedPasswords", JSON.stringify(passwords))
localStorage.setItem("savedLinks", JSON.stringify(links))
render()
})
document.getElementById("copy-btn").addEventListener("click", function() {
var input = document.getElementById("pw1-el").textContent;
navigator.clipboard.writeText(input);
alert("Copied Text: " + input);
})
index.html
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="index.css">
</head>
<body>
<div class="container">
<h1>Generate a</br>random password</h1>
<p>Never use an unsecure password again.</p>
<hr>
<div>
<label for="char-count-el">Character Count:</label>
<input type="number" id="char-count-el">
<button id="gen-btn"><span>Generate password</span></button>
</div>
<div>
<label>Your Password:</label>
<div class="pw-container">
<span class="password-line" id="pw1-el">...</span>
<button class="side-btn" id="save-btn">SAVE</button>
<button class="side-btn" id="copy-btn">COPY</button>
</div>
</div>
<div id="saved-passwords-container">
<hr>
<label>Saved Passwords:</label>
<div class="pw-container">
<div id="passwords-el">...</div>
<button class="side-btn" id="clear-btn">CLEAR</button>
</div>
</div>
</div>
<script src="index.js"></script>
</body>
</html>
index.css
body {
padding: 0;
margin: 0;
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
background-color: #ffffff;
color: white;
display: flex;
justify-content: center;
align-items: center;
}
h1::first-line {
color: white;
}
h1 {
color: #00ffaa;
margin-bottom: 5px;
line-height: 1;
}
label {
font-size: 11px;
display: block;
color: #D5D4D8;
margin-top: 10px;
}
input {
height: 38px;
border-radius: 5px;
border: none;
width: 70px;
padding: 0px 10px;
text-align: center;
background-color: #D5D4D8;
margin-right: 20px;
font-size: 14px;
}
.container {
background: #1F2937;
margin: 0;
padding: 10px 30px 40px;
width: 100%;
min-width: 500px;
box-shadow: 0px 10px 30px 10px #2640644b;
display: flex;
flex-direction: column;
}
.pw-container {
display: flex;
border-radius: 5px;
background-color: #3e4f66;
padding: 10px;
margin-top: 10px;
}
.password-line {
color: #00ffaa;
font-size: 16px;
padding: 5px 10px;
margin-top: 0px;
flex-grow: 1;
flex: 1 1 1;
min-width: 0;
word-wrap: break-word;
white-space: pre-wrap;
word-break: break-word;
}
#passwords-el {
padding-right: 30px;
flex-grow: 1;
flex: 1 1 0;
min-width: 0;
word-wrap: break-word;
white-space: pre-wrap;
word-break: break-word;
}
.saved-password-line {
color: #D5D4D8;
font-size: 14px;
padding: 10px 15px;
border-bottom: solid 1px #d5d4d814;
border-radius: 5px;
margin-bottom: 10px;
line-height: 0.9;
}
a {
color: #d5d4d872;
text-decoration: underline;
}
.side-btn {
font-size: 12px;
width: 60px;
border: none;
background: none;
color: #D5D4D8;
padding: 5px 10px;
border-radius: 5px;
justify-self: flex-end;
}
.side-btn:hover {
background-color: #ffffff28 ;
}
#gen-btn {
color: #ffffff;
background: #0EBA80;
text-transform: capitalize;
text-align: center;
width: 200px;
height: 40px;
padding: 10px 10px;
border: none;
border-radius: 5px;
margin-bottom: 10px;
margin-top: 10px;
transition: all 0.5s;
box-shadow: 0px 0px 30px 5px #0eba8135
}
#gen-btn:hover {
box-shadow: 0px 0px 30px 10px #0eba8157
}
#gen-btn span {
cursor: pointer;
display: inline-block;
position: relative;
transition: 0.5s;
}
#gen-btn span:after {
content: '\279c';
position: absolute;
opacity: 0;
top: 0;
right: -20px;
transition: 0.5s;
}
#gen-btn:hover span {
padding-right: 25px;
}
#gen-btn:hover span:after {
opacity: 1;
right: 0;
}
p {
color: #D5D4D8;
margin-top: 0px;
}
hr {
border-width: 1px 0px 0px 0px;
border-color: #95959576;
margin: 15px 0;
}
subtest.json
{
"manifest_version": 3,
"version": "1.0",
"name": "Password Generator",
"action": {
"default_popup": "index.html",
"default_icon": "icon.png"
},
"permissions": [
"tabs"
]
}
I am trying to deploy my first javascript application, which is a Chrome extension.
This simply generates random passwords and stores it with the url of current active tab.
App runs fine on local but after deploying it to Chrome, I got this error:
Uncaught TypeError: Cannot read properties of null (reading 'length')
index.js:65 (anonymous function)
I am a beginner, so any kind of criticism about my code is highly appreciated.
Thank you so much.
function render() {
*line65* **if(passwords.length === 0)** {
document.getElementById("saved-passwords-container").style.display= "none";
} else {
document.getElementById("saved-passwords-container").style.display= "unset";
}
let list = ""
**for (let i = 0; i < passwords.length; i++)** {
list += `<div class="saved-password-line"><span>${passwords[i]}</span></br></br><span class="link"><a target='_blank'href='${links[i]}'>${links[i]}</a></span></div>`
}
document.getElementById("passwords-el").innerHTML = list
}
Here is the full index.js file:
var characters = [];
for (var i=32; i<127; i++)
characters.push(String.fromCharCode(i));
for( var i = 0; i < characters.length; i++){
if ( characters[i] === '<') {
characters.splice(i, 1);
i--;
}
}
for( var i = 0; i < characters.length; i++){
if ( characters[i] === '>') {
characters.splice(i, 1);
i--;
}
}
let pw1El = document.getElementById("pw1-el")
let pw1 = ""
let passwords = []
passwords = JSON.parse(localStorage.getItem("savedPasswords"))
let links = []
links = JSON.parse(localStorage.getItem("savedLinks"))
render()
document.getElementById("char-count-el").value = 20
document.getElementById("gen-btn").addEventListener("click", function() {
var charCount = document.getElementById("char-count-el").value
pw1 = ""
for(let i = 0; i < charCount; i++) {
let randomIndex = Math.floor(Math.random() * characters.length)
pw1 += (characters[randomIndex])
}
pw1El.textContent = pw1
})
document.getElementById("save-btn").addEventListener("click", function() {
passwords.push(pw1El.innerText)
chrome.tabs.query({active: true, currentWindow: true}, function(tabs){
links.push(tabs[0].url)
})
localStorage.setItem("savedPasswords", JSON.stringify(passwords))
localStorage.setItem("savedLinks", JSON.stringify(links))
render()
})
function render() {
**if(passwords.length === 0)** {
document.getElementById("saved-passwords-container").style.display= "none";
} else {
document.getElementById("saved-passwords-container").style.display= "unset";
}
let list = ""
**for (let i = 0; i < passwords.length; i++)** {
list += `<div class="saved-password-line"><span>${passwords[i]}</span></br></br><span class="link"><a target='_blank'href='${links[i]}'>${links[i]}</a></span></div>`
}
document.getElementById("passwords-el").innerHTML = list
}
document.getElementById("clear-btn").addEventListener("click", function() {
passwords = []
links = []
localStorage.setItem("savedPasswords", JSON.stringify(passwords))
localStorage.setItem("savedLinks", JSON.stringify(links))
render()
})
document.getElementById("copy-btn").addEventListener("click", function() {
var input = document.getElementById("pw1-el").textContent;
navigator.clipboard.writeText(input);
alert("Copied Text: " + input);
})
index.html
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" href="index.css">
</head>
<body>
<div class="container">
<h1>Generate a</br>random password</h1>
<p>Never use an unsecure password again.</p>
<hr>
<div>
<label for="char-count-el">Character Count:</label>
<input type="number" id="char-count-el">
<button id="gen-btn"><span>Generate password</span></button>
</div>
<div>
<label>Your Password:</label>
<div class="pw-container">
<span class="password-line" id="pw1-el">...</span>
<button class="side-btn" id="save-btn">SAVE</button>
<button class="side-btn" id="copy-btn">COPY</button>
</div>
</div>
<div id="saved-passwords-container">
<hr>
<label>Saved Passwords:</label>
<div class="pw-container">
<div id="passwords-el">...</div>
<button class="side-btn" id="clear-btn">CLEAR</button>
</div>
</div>
</div>
<script src="index.js"></script>
</body>
</html>
index.css
body {
padding: 0;
margin: 0;
font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
background-color: #ffffff;
color: white;
display: flex;
justify-content: center;
align-items: center;
}
h1::first-line {
color: white;
}
h1 {
color: #00ffaa;
margin-bottom: 5px;
line-height: 1;
}
label {
font-size: 11px;
display: block;
color: #D5D4D8;
margin-top: 10px;
}
input {
height: 38px;
border-radius: 5px;
border: none;
width: 70px;
padding: 0px 10px;
text-align: center;
background-color: #D5D4D8;
margin-right: 20px;
font-size: 14px;
}
.container {
background: #1F2937;
margin: 0;
padding: 10px 30px 40px;
width: 100%;
min-width: 500px;
box-shadow: 0px 10px 30px 10px #2640644b;
display: flex;
flex-direction: column;
}
.pw-container {
display: flex;
border-radius: 5px;
background-color: #3e4f66;
padding: 10px;
margin-top: 10px;
}
.password-line {
color: #00ffaa;
font-size: 16px;
padding: 5px 10px;
margin-top: 0px;
flex-grow: 1;
flex: 1 1 1;
min-width: 0;
word-wrap: break-word;
white-space: pre-wrap;
word-break: break-word;
}
#passwords-el {
padding-right: 30px;
flex-grow: 1;
flex: 1 1 0;
min-width: 0;
word-wrap: break-word;
white-space: pre-wrap;
word-break: break-word;
}
.saved-password-line {
color: #D5D4D8;
font-size: 14px;
padding: 10px 15px;
border-bottom: solid 1px #d5d4d814;
border-radius: 5px;
margin-bottom: 10px;
line-height: 0.9;
}
a {
color: #d5d4d872;
text-decoration: underline;
}
.side-btn {
font-size: 12px;
width: 60px;
border: none;
background: none;
color: #D5D4D8;
padding: 5px 10px;
border-radius: 5px;
justify-self: flex-end;
}
.side-btn:hover {
background-color: #ffffff28 ;
}
#gen-btn {
color: #ffffff;
background: #0EBA80;
text-transform: capitalize;
text-align: center;
width: 200px;
height: 40px;
padding: 10px 10px;
border: none;
border-radius: 5px;
margin-bottom: 10px;
margin-top: 10px;
transition: all 0.5s;
box-shadow: 0px 0px 30px 5px #0eba8135
}
#gen-btn:hover {
box-shadow: 0px 0px 30px 10px #0eba8157
}
#gen-btn span {
cursor: pointer;
display: inline-block;
position: relative;
transition: 0.5s;
}
#gen-btn span:after {
content: '\279c';
position: absolute;
opacity: 0;
top: 0;
right: -20px;
transition: 0.5s;
}
#gen-btn:hover span {
padding-right: 25px;
}
#gen-btn:hover span:after {
opacity: 1;
right: 0;
}
p {
color: #D5D4D8;
margin-top: 0px;
}
hr {
border-width: 1px 0px 0px 0px;
border-color: #95959576;
margin: 15px 0;
}
manifest.json
{
"manifest_version": 3,
"version": "1.0",
"name": "Password Generator",
"action": {
"default_popup": "index.html",
"default_icon": "icon.png"
},
"permissions": [
"tabs"
]
}
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发布评论
评论(2)
最初,保存的Passewwords
在localstorage
中不存在,因此localstorage.getItem('SavedPasswords')
将返回null
null 。
然后,您进行JSON.PARSE(null)
,它不会立即崩溃,因为null
首先被胁迫到字符串并变为'null'
然后将JSON优先处理,然后回到null
,因为带有内容的字符串null
是有效的JSON。
但是,您然后在其上进行.length
并崩溃。
解决方案是处理尚未设置该项目的情况并像JSON分解的空数组一样处理它。您可以这样做,例如使用无效的合并操作员??
:
let passwords = JSON.parse(localStorage.getItem("savedPasswords") ?? '[]')
或者,您可以像以前一样以[]
来保持初始化,但可以用实际值包装分配在某个条件下:
let passwords = []
const json = localStorage.getItem('savedPasswords')
if (json !== null) {
passwords = JSON.parse(json)
}
我个人喜欢在localstorage
中为结构化数据做的事情,这也是这样的,它还处理了其他事物(例如Invalid JSON)以某种方式存储在那里的情况(没有砖砌应用程序):
let passwords = []
try {
const data = JSON.parse(localStorage.getItem('savedPasswords'))
if (Array.isArray(data)) passwords = data
} catch {}
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我解决了。
我知道这一点(如果我错了,请纠正我)
如果本地存储为空,则解析时不会返回空数组。
显然,当我这样做时:
密码不再是一个数组。
相反,我使用:
但这只是将嵌套阵列在密码内推动。
因此,我添加了一个for循环,并使用IF语句来解决初始错误:
I solved it.
I understand that (please correct me if I'm wrong)
if the local storage is empty, it does not return an empty array when parsed.
Apparently, when I do:
passwords is no longer an array.
I instead use:
But that just pushes a nested array inside passwords.
So I added a for loop, and used an if statement to address the initial error: