Tag Archives: front end

[Solved] Front end error: Unknown custom element

report errors

chunk-vendors.js:2128 [Vue warn]: Unknown custom element: - did you register the component correctly? For recursive components, make sure to provide the “name” option. - did you register the component correctly?For recursive components, make sure to provide the "name" option

 

reason

el component not registered

Solution:

1. Download elementUI

npm i element-ui -S

2. Import

Add the following three lines  in main.js:

import ElementUI from 'element-ui';
import 'element-ui/lib/theme-chalk/index.css';
Vue.use(ElementUI);

Done!

eslint Error: Delete `␍` [How to Solve]

reason

Due to the end of line style configuration, endoofline configuration has the following four options:
lf – line feed only (\n), which is common in Linux, MacOS and git repos
CRLF – carriage return + line feed character (\r \n), and windows
CR – carriage return character only (\r), Rarely use
auto – keep the existing end of the line (the mixed values in a file are standardized by looking at the content used after the first line)

Solution:

Configure endOfLine: ‘auto’ in prettier.config.js:

module.exports = {
  semi: false, // unterminated semicolon
  singleQuote: true, // single quotes
  quoteProps: 'as-needed',
  trailingComma: 'none', // final comma
  
 // The point is that this one should be configured as auto
  endOfLine: 'auto'
}

[Solved] uni app TypeError: undefined is not an object (evaluating ‘modules[moduleId].call‘) __ERROR

The project runs normally on H5. When it is debugged and opened with the real machine, the app reports an error and a white screen appears.

Scene reproduction:

If the route jumps to the toapproval page, the above problem will occur.

Troubleshooting:

After step-by-step positioning and troubleshooting, the problem appears in the component of toapproval page

Firstly, the toapproval page is under the main business pages folder, but the workflowdetail component of this page is imported from the subcontracting pagesoa folder. This leads to a white screen in the business jump during real machine debugging. However, it is not so strict in H5 browser, so this problem will not occur and it is not easy to locate the problem.

Solution:

If you find the problem, you can easily solve it. You can change the name of this component, copy it to the components folder, and import it from the components folder again.

[Solved] Error in v-on handler “TypeError Cannot read properties of undefined (reading ‘resetFields‘)“

In the Vue element project, a new pop-up box function is added. I want to reset the form item every time I click Add
1.
this is used KaTeX parse error: Undefined control sequence:

atposition5:refs\–[–formName

Reset… Refs does not get the dom element, resulting in ‘resetfields’ of undefined

3. Solution:

Add code

this.$nextTick(()=>{
  this.$refs.addForm.resetFields();
})

How to Solve Uncaught (in promise) Error (Two Solutions)

Reporting an uncaught (in promise) error. The solution
There are two Solutions:

1. when using Axios to request an interface, add catch() behind then():

  1. export function stopMCUMixTranscode(params) {
return new Promise((resolve, reject) => {
axios
.post(********, params)
.then((res) => {
resolve(res)
})
.catch((err) => {
reject(err)
})
})
}

     

2. Use return promise Reject (new error (res.msg | ‘error’)) to catch and handle exceptions. It needs to be use .catch(err=>{console.log(err)}) to catch exceptions when the request comes back,

return Promise.reject(error).catch(err=>{console.log(err)}) // Return the error message returned by the interface

[Solved] fastjson Error: write javaBean error, fastjson version 1.2.76, class io.undertow.servlet.xx

Error message:

com. alibaba. fastjson. JSONException:

write javaBean error, fastjson version 1.2.76, class io. undertow. servlet. spec.HttpServletResponseImpl, fieldName : 0,

write javaBean error, fastjson version 1.2.76, class io. undertow. server. HttpServerExchange, fieldName : exchange,

UT010034: Stream not in async mode

code:

    @ApiOperation(value = "TEST",notes = "")
    @PostMapping("/abccc")
    @ResponseBody
    public void test( HttpServletResponse response) {
        //service
    }

Solution:

Remove this swagger comment.

@ApiOperation(value = "TEST",notes = "")

Notes of swagger, @ apioperation (value = “interface description”, httpmethod = “interface request method”, response = “interface return parameter type”, notes = “interface release description”);

That’s right!!!!! There are no bugs!!!!!

Complete error reporting information:

2021-09-01 11:14:36.911 [XNIO-1 task-1] ERROR x.x.x.framework.exception.GlobalExceptionHandler - url=http://xxx.x.x.x:xxxxx/shell/abccc,errormsg=com.alibaba.fastjson.JSONException: write javaBean error, fastjson version 1.2.76, class io.undertow.servlet.spec.HttpServletResponseImpl, fieldName : 0, write javaBean error, fastjson version 1.2.76, class io.undertow.server.HttpServerExchange, fieldName : exchange, UT010034: Stream not in async mode
	at com.alibaba.fastjson.serializer.JavaBeanSerializer.write(JavaBeanSerializer.java:544)
	at com.alibaba.fastjson.serializer.JavaBeanSerializer.write(JavaBeanSerializer.java:154)
	at com.alibaba.fastjson.serializer.JSONSerializer.writeWithFieldName(JSONSerializer.java:360)
	at com.alibaba.fastjson.serializer.JSONSerializer.writeWithFieldName(JSONSerializer.java:338)
	at com.alibaba.fastjson.serializer.ObjectArrayCodec.write(ObjectArrayCodec.java:118)
	at com.alibaba.fastjson.serializer.JSONSerializer.write(JSONSerializer.java:312)
	at com.alibaba.fastjson.JSON.toJSONString(JSON.java:793)
	at com.alibaba.fastjson.JSON.toJSONString(JSON.java:731)
	at com.alibaba.fastjson.JSON.toJSONString(JSON.java:688)
	at com.xxxxx.xxxxx.xxxxx.controller.xxxxxController.test(ShellInfoController.java:40)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
	at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
	at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:104)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:892)
	at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:797)
	at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
	at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1039)
	at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:942)
	at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1005)
	at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:908)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:665)
	at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:882)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:750)
	at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
	at org.springframework.boot.actuate.web.trace.servlet.HttpTraceFilter.doFilterInternal(HttpTraceFilter.java:88)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
	at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
	at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:92)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
	at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:93)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.filterAndRecordMetrics(WebMvcMetricsFilter.java:114)
	at org.springframework.boot.actuate.metrics.web.servlet.WebMvcMetricsFilter.doFilterInternal(WebMvcMetricsFilter.java:104)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
	at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:200)
	at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:109)
	at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
	at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
	at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
	at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
	at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
	at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
	at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:132)
	at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
	at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
	at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
	at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
	at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
	at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
	at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
	at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
	at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
	at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
	at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
	at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
	at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
	at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
	at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
	at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
	at io.undertow.server.Connectors.executeRootHandler(Connectors.java:364)
	at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:830)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: com.alibaba.fastjson.JSONException: write javaBean error, fastjson version 1.2.76, class io.undertow.server.HttpServerExchange, fieldName : exchange, UT010034: Stream not in async mode
	at com.alibaba.fastjson.serializer.JavaBeanSerializer.write(JavaBeanSerializer.java:544)
	at com.alibaba.fastjson.serializer.JavaBeanSerializer.write(JavaBeanSerializer.java:154)
	at com.alibaba.fastjson.serializer.FieldSerializer.writeValue(FieldSerializer.java:318)
	at com.alibaba.fastjson.serializer.JavaBeanSerializer.write(JavaBeanSerializer.java:475)
	... 81 more
Caused by: java.lang.IllegalStateException: UT010034: Stream not in async mode
	at io.undertow.servlet.spec.ServletOutputStreamImpl.isReady(ServletOutputStreamImpl.java:757)
	at com.alibaba.fastjson.serializer.ASMSerializer_11_ServletOutputStreamImpl.write(Unknown Source)
	at com.alibaba.fastjson.serializer.FieldSerializer.writeValue(FieldSerializer.java:318)
	at com.alibaba.fastjson.serializer.JavaBeanSerializer.write(JavaBeanSerializer.java:475)
	... 84 more

[vite] http proxy error: Error: self signed certificate in certificate chain vite

In order to prevent cross domain problems when requesting interfaces, vite proxy is used for configuration.

For example, the address of the request interface is https://172.1.1.0:8080 , the vite configuration information is as follows:

...

server: {
        host: '0.0.0.0',
        port: 12000,
        proxy: {
            '/local/': {
                target: 'https://172.1.1.0:8080',
                changeOrigin: true,
                rewrite: (path) => path.replace(/^\/local\//, ''),
            },
        },
},

...

Local requests are all interfaces. You only need to add a prefix -/local /. For example, the login interface is’/local/Login ‘.

So I went to request and found that the error was reported directly. The error information is as follows:

[vite] http proxy error: Error: self signed certificate

The certificate is wrong.

Solution: add a configuration – secure: false The overall configuration code is as follows:

proxy: {
            '/local/': {
                target: '',
                

                // Add
                secure: false,
                // End




                changeOrigin: true,
                rewrite: (path) => path.replace(/^\/local\//, ''),
            },
        },

Then try again. Sure enough, there’s no problem.

Parsing error:x-invalid-end-tag [How to Solve]

Parsing error:x-invalid-end-tag

Reason: When iView renders tags as native html tags, some tags are self-closing, such as input, so having end tags will report an error.
Solution 1: Remove the end tag.
Solution 2: Modify the configuration file to ignore the check.
root directory - eslintrc.js - Rules
add a line: "Vue/no parsing error": [2, {"x-invalid end tag": false}]

[Solved] Error Rule can only have one resource source (provided resource and test + include + exclude)

Error: Rule can only have one resource source
(provided resource and test + include + exclude)

Error: Rule can only have one resource source (provided resource and test + include + exclude)

Error: Rule can only have one resource source (provided resource and test + include + exclude) in
 "exclude": [
    null
  ],
  "use": [
    {
      "loader": "/Users/juanpablo/front-treatments/node_modules/cache-loader/dist/cjs.js",
      "options": {
        "cacheDirectory": "/Users/juanpablo/front-treatments/node_modules/.cache/babel-loader",
        "cacheIdentifier": "81fef5a6"
      },
      "ident": "clonedRuleSet-38[0].rules[0].use[0]"
    },
    {
      "loader": "/Users/juanpablo/front-treatments/node_modules/babel-loader/lib/index.js",
      "options": "undefined",
      "ident": "undefined"
    }
  ]
} ````
A complete log of this run can be found in:
0 info it worked if it ends with ok
1 verbose cli [
1 verbose cli   '/Users/juanpablo/.nvm/versions/node/v12.19.0/bin/node',
1 verbose cli   '/Users/juanpablo/.nvm/versions/node/v12.19.0/bin/npm',
1 verbose cli   'run',
1 verbose cli   'serve'
1 verbose cli ]
2 info using [email protected]
3 info using [email protected]
4 verbose run-script [ 'preserve', 'serve', 'postserve' ]
5 info lifecycle [email protected]~preserve: [email protected]
6 info lifecycle [email protected]~serve: [email protected]
7 verbose lifecycle [email protected]~serve: unsafe-perm in lifecycle true
8 verbose lifecycle [email protected]~serve: PATH: /Users/juanpablo/.nvm/versions/node/v12.19.0/lib/node_modules/npm/node_modules/npm-lifecycle/node-gyp-bin:/Users/juanpablo/front-treatments/node_modules/.bin:/Users/juanpablo/.nvm/versions/node/v12.19.0/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Users/juanpablo/.rvm/bin
9 verbose lifecycle [email protected]~serve: CWD: /Users/juanpablo/front-treatments
10 silly lifecycle [email protected]~serve: Args: [ '-c', 'vue-cli-service serve' ]
11 silly lifecycle [email protected]~serve: Returned: code: 1  signal: null
12 info lifecycle [email protected]~serve: Failed to exec serve script
13 verbose stack Error: [email protected] serve: `vue-cli-service serve`
13 verbose stack Exit status 1
13 verbose stack     at EventEmitter.<anonymous> (/Users/juanpablo/.nvm/versions/node/v12.19.0/lib/node_modules/npm/node_modules/npm-lifecycle/index.js:332:16)
13 verbose stack     at EventEmitter.emit (events.js:314:20)
13 verbose stack     at ChildProcess.<anonymous> (/Users/juanpablo/.nvm/versions/node/v12.19.0/lib/node_modules/npm/node_modules/npm-lifecycle/lib/spawn.js:55:14)
13 verbose stack     at ChildProcess.emit (events.js:314:20)
13 verbose stack     at maybeClose (internal/child_process.js:1021:16)
13 verbose stack     at Process.ChildProcess._handle.onexit (internal/child_process.js:286:5)
14 verbose pkgid [email protected]
15 verbose cwd /Users/juanpablo/front-treatments
16 verbose Darwin 19.6.0
17 verbose argv "/Users/juanpablo/.nvm/versions/node/v12.19.0/bin/node" "/Users/juanpablo/.nvm/versions/node/v12.19.0/bin/npm" "run" "serve"
18 verbose node v12.19.0
19 verbose npm  v6.14.8
20 error code ELIFECYCLE
21 error errno 1
22 error [email protected] serve: `vue-cli-service serve`
22 error Exit status 1
23 error Failed at the [email protected] serve script.
23 error This is probably not a problem with npm. There is likely additional logging output above.
24 verbose exit [ 1, true ]

Cause analysis:

Webpack version conflict in package.json.

Solution:

Delete the webpack and reinstall the previous version
npm uninstall webpack
npm install webpack@^4.0.0 –save-dev

[Solved] NPM Start Project Error: ‘Error: error:0308010C:digital envelope routines::unsupported’

Reason: the version of node is higher than 16, the version of the project is not higher than 16, and OpenSSL is updated after node17.

Solution:

Method 1:

Modify the environment variable at the command line: $env:NODE_OPTIONS="--openssl-legacy-provider"
In the start project: yarn start
Method 2.
Use nvm to modify the node to a version no higher than 16

Websocket Front-end Call Example 

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
</head>
<body>
Welcome<br/><input id="text" type="text"/>
<button onclick="send()">Send message</button>
<hr/>
<button onclick="closeWebSocket()">Close WebSocket connection</button>
<hr/>
<div id="message"></div>
</body>
<script>
var websocket = null;
// determine if the current browser supports WebSocket
if ('WebSocket' in window) {
	websocket = new WebSocket("ws://localhost:8080/wsServer");
}
else {
	alert('The current browser does not support websocket')
}

// Callback method for connection error
websocket.onerror = function () {
	setMessageInnerHTML("An error occurred with the WebSocket connection");
};

// Callback method for successful connection establishment
websocket.onopen = function () {
	setMessageInnerHTML("WebSocket connection successful");
}

// Callback method for received message
websocket.onmessage = function (event) {
	setMessageInnerHTML(event.data);
}

// Callback method for closing the connection
websocket.onclose = function () {
	setMessageInnerHTML("WebSocket connection closed");
}

// Listen to the window close event and actively close the websocket connection when the window is closed to prevent the window from being closed before the connection is broken, which will throw an exception on the server side.
window.onbeforeunload = function () {
	closeWebSocket();
}
 
// Display the message on the web page
function setMessageInnerHTML(innerHTML) {
	document.getElementById('message').innerHTML += innerHTML + '<br/>';
}
 
//Close the WebSocket connection
function closeWebSocket() {
	websocket.close();
}
 
//Send a message

function send() {
var message = document.getElementById('text').value;
	websocket.send(message);
}
</script>

</html>