Unable to resolve dependency 'Telerik.Sitefinity.AmazonCloudSearch'. First to understand the problem. Npm, Npm ERR! Problem: Unable to resolve dependencies of NuGet packages. Connect and share knowledge within a single location that is structured and easy to search. I am having an issue where when I try to install various root packages, it has trouble installing dependent packages. Also, I suspect that there are some jar which we don't need to the project because they were old dependencies of old tool that we needed in the past but they were replaced by others. downgrading Angular and the global Angular CLI version to version that will satisfy the requirement. ERESOLVE unable to resolve dependency packages have unmet dependencies - unable to install packages; packages have unmet dependencies - unable to install packages npm cache clean --force after npm i --force, Option 2: run npm install --save --legacy-peer-deps, The problem seems to be that gf-kautomata-pipeline-ui is using Angular 9, while @angular/http requires Angular 7. Does squeezing out liquid from shredded potatoes significantly reduce cook time? I simply forgot to upgrade Angular CLI. How to create a JavaScript Dictionary and add key value pairs. As you see, it fires the following error: No matching version found for @angular/http@^9.1.4. P.S. npm ERR! (@angular/http was deprecated and eventually removed, and all its functionality was moved into @angular/common instead. On the other go1.18 just got released, and it will take some time until all the ecosystem will align with the newest changes. How do I simplify/combine these two methods for finding the smallest and largest int in an array? @alentejo by removing the npm folder in theC:\Users\{your name}\AppData\Roaming , npm cache clear --force and then npm install -g npm@. 2022 Moderator Election Q&A Question Collection, How can I fix ERESOLVE unable to resolve dependency tree for npm install, Is there any way to configure multiple registries in a single npmrc file, npm: When to use `--force` and `--legacy-peer-deps`. Making statements based on opinion; back them up with references or personal experience. We will never spam you. Does clearing cache help here? Solution class missing import. The problem is related to a dependency conflict or broken dependency. NPM can be used to install and manage versions of dependencies in your projects. Is it OK to check indirectly in a Bash if statement for exit codes if they are multiple? Problem: Could not load assembly reference, In the toolbar of Visual Studio, navigate to, Confirm that the Sitefinity NuGet Server (. What is the purpose of the 'node_modules' folder? Solution setup JDK. You can also set this permanently by adding this into a configuration by running the below command. Many programming languages like C# and, Unable to resolve dependency tree error when installing npm packages. When you upgrade the site by installing Telerik.Sitefinity.All NuGet package, Visual Studio throws the following error: Unable to resolve dependencies. Can an autistic person with difficulty making eye contact survive in the workplace? And the top message says that the angular common found is actually 11.0.3. warning: cannot resolve "nvidia-450xx-utils=450.80.02", a dependency of "linux57-nvidia-450xx" warning: cannot resolve "nvidia-450xx-utils=450.80.02", a . : I am using the temporary workaround until npm 7 works fine with my project: after that, I will delete yarn.lock, package-lock.json and folder node_modules, and recompile with npm. To learn more, see our tips on writing great answers. It gives errors in the npm 7 version and cannot install Node.js modules. We and our partners use data for Personalised ads and content, ad and content measurement, audience insights and product development. Unable to resolve dependency package problem. Step 3:Clear the npm cache and perform the clean installation with --force flag as shown below. Rebuild the project . npm ERR! Node Package Manager (npm) as the name indicates it is, Table of Contents Hide What is Node.js?Who Developed Node JS?Node.js OS supportFeatures of Node.js#1. The bundle is built using maven and it imports gson. This will downgrade npm. So this npm install -g @angular/cli@latest solved my errors during ng new abc. Iam getting a problem while install media player packages. Replacing outdoor electrical box at end of conduit, Two surfaces in a 4-manifold whose algebraic intersection number is zero. As you are using 12.04 a stable version, I think this will do the trick otherwise you can do. The --legacy-peer-deps tells the npm to ignore the peer dependencies and continue the installation of the package. New ("unable to resolve root package") ErrRootPkgNotResolved is returned when the root Pkg of the Tree cannot be resolved, typically because it does not exist. That's the best answer because it is the only answer which explained the error log from OP instead of stupidly applying force or legacy-peer-deps option. In this article lets see how to create a JavaScript Dictionary and add key-value pairs. Is this going to work for you? Boost your credentials through advanced courses and certification. Thanks for contributing an answer to Ask Ubuntu! So what is missing is that karcin-insight-rest bundle has Import-Package: tr.com.karcin.license, but you didn't install any bundle that has the same package in Export-Package. Once you've found a package of interest, you can either install it using the + character or remove/deselect it from the list. The best answers are voted up and rise to the top, Not the answer you're looking for? I prefer women who cook good food, who speak three languages, and who go mountain hiking - what if it is a woman who only has one of the attributes? Some of our partners may process your data as a part of their legitimate business interest without asking for consent. Many developers are facing this issue while installing the dependencies in angular projects. How can I change the version of npm using nvm? "Package dependencies cannot be resolved" while installing Chromium browser, Dependencies | not able to install from Ubuntu Software Center | Ubuntu 14.04, Package dependencies cannot be resolved - R project, "Package dependencies cannot be resolved" error while installing Wine in Ubuntu 12.1, Banshee package dependencies cannot be resolved, Unmet dependencies when trying to install r-base, Correct handling of negative chapter numbers. Probably, yes. You have dependency conflict (incorrect and potentially broken dependency) as it says, so try to run the command with --force, or --legacy-peer-deps. If the letter V occurs in a few native words, why isn't it included in the Irish Alphabet? Restore the dependencies and tools for the project in the current directory using the two file paths provided as sources: .NET CLI. I am unable to start a bundle in Karaf (version 3.0.1). @agm/[email protected]"3.0.0-beta.0" from the root project dependencies these are the essential dependencies that you rely on and call in your project's code devDependencies these are your development dependencies, for example, a prettier library for formatting code peerDependencies if you set a peer dependency in your package . Online free programming tutorials and code examples | W3Guides. 1. Should we burninate the [variations] tag? dotnet restore -s c:\packages\mypackages -s c:\packages\myotherpackages. Yarn has a feature for solving this. Generalize the Gdel sentence requires a fixed point theorem. Why does the sentence uses a question form, but it is put a period in the end? How do I completely uninstall Node.js, and reinstall from beginning (Mac OS X), How to fix npm throwing error without sudo, Cannot install packages using node package manager in Ubuntu. All executable tools share same data struct definitions (model) under internal folder.. To generate api tool swagger document, I ran ./swag init -g cmd/api/main.go -o cmd/api/docs. You have dependency conflict ( incorrect and potentially broken dependency) as it says, so try to run the command with --force, or --legacy-peer-deps. The problem is about peer dependencies. Please, Unable to resolve dependency tree error when installing npm packages, https://www.npmjs.com/package/@angular/http, this amazing answer on how to scope packages, Making location easier for developers with new data primitives, Stop requiring only one assertion per unit test: Multiple assertions are fine, Mobile app infrastructure being decommissioned. In my case I was having trouble with a @babel/core dependency, but I didn't want to use --force, because I was not sure about the consequences, so I went to https://www.npmjs.com/, looked for the package and replaced my old version with the newest one. NPM's package (dependency) management mechanism allows packages (dependencies) to have: (direct) dependencies - installed automatically with the package; peer dependencies - have to be manually installed by the consumer of the package. Source(s) used: 'Sitefinity NuGet Server', 'nuget.org', 'Microsoft Visual Studio Offline Packages. Single Threaded and Highly Scalable#4. If you will downgrade npm version to 6, those problems will become warnings and the problem will be resolved. You can proceed by accepting the incorrection of dependency by forcing an install. ERESOLVE unable to resolve dependency tree'. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. Take a look at the official NPM documentation onlegacy-peer-depsfor more info about peer dependencies in npm v7. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. 2 min read. Note that the latest version for that deprecated package is 7.2.16 while you request an upper version (e.g., ^9.1.4)! You can set this option to true by default (not recommended by npm): Or just wait until these packages get up to date. to get the newest packages index and then repeat the first commands. my @angular/core version is 9.1.4, so shall i update @angular/http? Sign in The easiest way to fix the issue is to pass an additional parameter legacy-peer-deps to npm install. What is the meaning of the "at" (@) prefix on npm packages? command failed Errors. Delete all packages from the packages folder. To fix Unable to resolve dependency tree error in Angular while installing `npm` packages follow the below steps. How to fix Unable to resolve dependency tree error when installing npm packages? To access this repository, I created an .npmrc file. In this case KR100048 was the bad guy. As you are using 12.04 a stable version, I think this will do the trick otherwise you can do. Well occasionally send you account related emails. ERESOLVE unable to resolve dependency tree npm ERR! By far the best answer, others just fix the issue, but not caring about the underlying problem nor give insightful suggestions on why the issue is occurring. It gave me error unable to resolve dependency tree and based on the help information from this command, The fastest solution: npm install --legacy-peer-deps. If you do this, it might actually work, but may god have mercy on you, because you're DEFINITELY running some libraries that are incompatible with your current version of Angular. Connect and share knowledge within a single location that is structured and easy to search. Ubuntu 22.10 has been released, and posts about it are no longer (generally) how to install wine windows program loader? Is there a trick for softening butter quickly? Find centralized, trusted content and collaborate around the technologies you use most. sudo apt-get autoclean to clean up any partial packages var ErrRootPkgNotResolved = errors. I suggest you to do these: (most of the cases, it works), Install aptitude with sudo apt-get install aptitude command, Try to install the package you are willing to install with command like, Aptitude will show you the error and present you a possible (best) solution. Can you share the package.json file? Manage Settings If, while doing this, you can identify the broken package, this command will very forcefully remove it: sudo dpkg --remove -force --force-remove-reinstreq packagename Because of this, the npm install command would search all packages in my private repository and not in npm feed any more. When you enter your query, you will be able to dynamically update the package results. So --legacy-peer-deps does not try to install the peerDependencies automatically. Let me know if it work. So, try to check the project dependencies and follow the raised errors in order to solve the problem. Input to NuGet restore is a set of PackageReference items from the project file (top-level or direct dependencies) and the output is a full closure of all the package dependencies including transitive dependencies. Go to ubuntu software center >> Edit >> Software Sources >> Download From >> Select United States After that restart your computer go to software center and type wine and install it, sudo apt-get update to update your package list TheUnable to resolve dependency tree error when installing npm packagesoccurs when you install the node dependencies with the latest version of NPM(v7). The relevant dependency management code is in npm. Use of legacy-peer-deps is not recommended, as it will not enforce the peerDependencies contract that meta-dependencies may rely on. to your account, Upgrading our project to Go1.18 leads to swag raising an error message. Stack Overflow for Teams is moving to its own domain! Blogger, Traveller, Investor and Technologist. When using npm 7, this comes up a lot because peer dependencies issues are treated as errors in version 7 whereas they were generally only warnings in version 6. 'Progress.Sitefinity.Authentication 10.0.6421' is not compatible with 'Telerik.Sitefinity.Core 10.1.6523 Unable to resolve dependency 'Telerik.Sitefinity.AmazonCloudSearch'. However, NPM does not allow multiple versions of the same package to coexist. What is causing the ERESOLVE unable to resolve dependency tree? Is cycling an aerobic or anaerobic exercise? If you see that your desired package is not listed in the (will be) installed list, simply press n to let aptitude give you the next best solution. Replacing outdoor electrical box at end of conduit. Let's configure the plugin to use. What is the effect of cycling on weight loss? What is Unable to resolve dependency tree error when installing npm packages? While resolving: project-admin@11.. npm ERR! privacy statement. The -f or --force argument will force npm to fetch remote resources even if a local copy exists on disk. So I did the basic troubleshooting in those cases : Open the SCCM Console Navigate to Software Library\Operating Systems\Task Sequences Click Reference tab at the bottom Locate the problematic ID ( KR100048) Note the package Name ( Windows x64 - HP ProBook 650 G1) First problem : the Size column is 0.00MB ?! Another option that is less disruptive than downgrading npm is using npx to use the previous version of npm for just the install command: npx -p npm@6 npm install. I saw another Github issue and think the issue might be related to the use of the parseDependency flag and the changes to go mod. Why don't we consider drain-bulk voltage instead of source-bulk voltage in body effect? All Rights Reserved. https://github.com/KyleBanks/depth. If you're running Angular 7, then open up your package.json and check to make sure all of your Angular packages are no higher than ^7.0.0. METHODS TRIED i have tried adding GOOGLE MAVEN REPO, mavencentral all with url & without url. Let us look at each of those in detail. What does puncturing in cryptography mean. How can I get a huge Saturn-like ringed moon in the sky? How to resolve ngx-bootstrap error in Angular-14. Your command will be like npm install --force @your-npm-package. code ERESOLVE unable to resolve dependency tree So my decision was not to use this package and to find an alternative. Your feedback about this content is important. If a package cannot be installed because of overly strict The following information may help to resolve the situation: The following packages have unmet dependencies: kali-linux-full : Depends: beef-xss but it is not going to be installed E: Unable to correct problems, you have held broken packages. Copy. If using npm 5 or greater no need --save flag as it automatically saves dependencies. Npm Npm ERR! However, I can directly install the dependent package without issues (and then the root package). At last I found a solution: ERESOLVE unable to resolve dependency tree. That did the work. Modified 5 years, . And finally, execute your command. Have a question about this project? Most of the developers use the wrong approach of emptying the array in JS. . At the end installing about five packages manually, all with --legacy-peer-deps, I ended to a package that could not be installed and I did not try to continue, because my project was throwing warnings like crazy and there were a lot of packages for audit too. You signed in with another tab or window. The differences between the two are below . Downgrading Node.js is not necessary (but not harmful either). I had it the same issue on React versions in relation with the npm version: So it might be package-versions that need to be installed based on your package.json file. Iterate through addition of number sequence until a single digit, Two surfaces in a 4-manifold whose algebraic intersection number is zero. Source(s) . You may also need remove gf-kautomata-pipeline-ui, or contact the author of gf-kautomata-pipeline-ui and find out if the library is compatible with Angular 7. Why is SQL Server setup recommending MAXDOP 8 here? To view the purposes they believe they have legitimate interest for, or to object to this data processing use the vendor list link below. And when all else fails, it's often worth a shot to remove the node_modules directory and package-lock.json, and then run npm install again. Can i pour Kwikcrete into a 4" round aluminum legs to add support to a gazebo. Why are only 2 out of the 3 boosters on Falcon Heavy reused? Hello everyone I wanted to update my system using sudo pacman -Syyu that I got this error::: Starting full system upgrade. npm ERR! rev2022.11.3.43005. Try npm cache clean --force. Try with sudo apt-get install -f , I've been getting these errors too. Unable to resolve dependency 'chocolatey-core.extension (= 1.3.3)'. We and our partners use cookies to Store and/or access information on a device. See Trademarks for appropriate markings. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. If you can, try to use it for installing the package. I included gson in maven as required: to get the newest packages index and then repeat the first commands. The text was updated successfully, but these errors were encountered: If you have node_modules folder and package-lock.json file in your root directory then remove those: Create .env file in the root directory and paste below code: I have faced this issue many times. It half-installs Angular 7, and half-installs angular 9. Synchronizing package databases. npm ERESOLVE unable to resolve dependency tree NestJs Passport, Angular NPM install but getting ERESOLVE unable to resolve dependency tree npm ERR! no servers configured for repository Failed to synchronize databases Resolving dependencies. Rollback to the working version of package.json + package-lock.json and add packages turned out to be the safest and fastest variant for me. Functions This section is empty. As of npm v7, peerDependencies are installed by default. So what should be the solution then? We can resolve the ERESOLVE unable to resolve dependency tree by using the --force flag while installing the dependencies, or we can ignore the peerDependencies by passing an additional argument --legacy-peer-deps. The plugin uses a lot of different rules, but we are only interested in one: dependencyConvergence - ensures all dependencies converge to the same version. By clicking Sign up for GitHub, you agree to our terms of service and when i use --parseInternal --parseDependency --parseDepth=100 to genarate doc, will happen error, Go1.18: cannot find all dependencies, unable to resolve root package. Can you try to delete package-lock.json and node_modules and try to run npm update? The consent submitted will only be used for data processing originating from this website. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Open the terminal and try the following commands: That's how I mostly fix dependency problems. (If you want to understand dependencies little bit better, here is very simple site: How npm3 Works). 'Progress.Sitefinity.Authentication 10.0.6421' is not compatible with 'Telerik.Sitefinity.Core 10.1.6523 Ask Ubuntu is a question and answer site for Ubuntu users and developers. You might try to use the. Try the below command to install the dependencies for your project. Try this: Open the terminal and try the following commands: sudo dpkg --configure -a sudo apt-get install -f. That's how I mostly fix dependency problems. For consent downgrading Angular and the community time I comment in Azure DevOps to check indirectly a. Parents do PhDs resolve the problem PackageReference list has not changed use yarn to install with the root ). Satisfy to installation request no matching version found for @ angular/http was deprecated and eventually removed, and will! The peerDependencies automatically is there something like Retr0bright but already made and trustworthy Irish Alphabet in! Why are only 2 out of the 'node_modules ' folder npm 5 or greater no need save! The code above ) find an alternative emptying the array in JS of package.json + and We and our partners use data for Personalised ads and content, ad and content, and Answers are voted up and rise to the desired version ( e.g. ^9.1.4 It automatically saves dependencies the package you want to understand dependencies little better! Visual Studio Offline packages how many characters/pages could WordStar hold on a typical machine! Ever been done Ubuntu developers doing, only focused on GUI step change until you can proceed by the! You see, it tells npm to ignore peer deps and proceed with root Of npm v7, peerDependencies are installed by default empty an array with JavaScript is deepest! And bundle using yarn install data being processed may be a unique identifier stored in a cookie fires May be a unique identifier stored in a cookie a few native,! Greater no need -- save flag as shown below used to install the dependencies Angular. Why do n't we consider drain-bulk voltage instead of ` npm install -- force @ your-npm-package needed Technologies you use most in Azure DevOps was deprecated and eventually removed, and all its functionality was into May also need remove gf-kautomata-pipeline-ui, or responding to other answers introducing abstractions for that. 5 years, 7 months ago often downgrade npm as well tree a. Downgrading Node.js will often downgrade npm as well tree npm ERR was deprecated and eventually,. Some peerDependencies that conflict with the root package ) to avoid fixing your dependencies issues the trick you! = 1.3.3 ) & # x27 ; s configure the plugin to use for! From version 6 to 7. npm ERR the bottom to the latest available version ) 5 that has ever done, your answer, you should start to read the problem, perform the clean installation with -- @! Let us know dependencies issues kali-arm64: ~ # apt-get -f install Reading package lists Passport. Our free beginner training using -- legacy-peer-deps does not try to run npm update are!: sign up for GitHub, you agree to our terms of and. Angular npm install fails ( unable to resolve the problem, perform the following commands: that how! The desired version ( e.g., ^9.1.4 ) the sentence uses a question and answer site for Ubuntu users developers I have as error: no matching version found for @ angular/http made and trustworthy you 're for! To the working version of package.json + package-lock.json and node_modules and try run! Map in layout, simultaneously with items on top your answer, you should start to the Resolve dependency tree NestJs Passport, Angular npm install but getting ERESOLVE unable resolve. At last I found a solution: ERESOLVE unable to resolve dependency tree when! Project dependencies and follow the raised errors in the workplace without issues ( and then the! 3.0.0-Beta.0 requires Angular common or the solution is to downgrade to npm install -- save flag as used Modules correctly subsequent npm runs to version that will satisfy the requirement Angular Usually do n't we consider drain-bulk voltage instead of source-bulk voltage in body effect order to solve the problem related! With JavaScript is the best answers are voted up and rise to the latest version for that deprecated is! So will often downgrade npm version 3 to 6, those problems will become warnings and the community package install! The bottom to the desired version ( e.g., ^9.1.4 ) newest changes project Getting these errors were contributions licensed under CC BY-SA solution: ERESOLVE to! Prefix on npm packages installed by default may contain exact commands needed to run installing packages. Need remove gf-kautomata-pipeline-ui, or responding to other answers those in detail yarn package manager used some packages from private. Successfully, but these errors were Import ( name, email, and bundle using yarn install clarification! Rely on pour Kwikcrete into a 4 '' round aluminum legs to add support to a dependency or From the code above ) version ( note: if not upgrading to the latest version for concepts. Answer site for Ubuntu users and developers terminal and try to install the dependencies for project Each tool has its own domain tool has its own domain conclude where the issue may be a unique stored This is definitely the most accurate answer, you should start to the! Working version of package.json + package-lock.json and add packages turned out to be the safest fastest! Air inside of data being processed may be a unique identifier stored in a native. They were the `` best '' install wine windows program loader can be used for data originating. Error: no matching version found for @ angular/http was deprecated and eventually removed, it! & amp ; without url Overflow for Teams is moving to its own domain I! Will downgrade npm version 3 to 6 as it automatically saves dependencies 6, those problems will become warnings the. Be that this dependency does n't require downgrading Angular and the global Angular CLI version to, Package and to find an alternative n't work for me package ) see Of our partners use data for Personalised ads and content measurement, audience insights and product development peerDependencies that with The yarn package manager the standard initial position that has ever been done program?! Activating the pump in a 4-manifold whose algebraic intersection number is zero tools for the project in the sky for! Please update your cookie Settings and allow the usage of Functional Cookies for Personalised and And, unable to resolve dependency tree ), Heroku Shopify Application error 'npm ERR until can. Newest changes were the `` at cannot find all dependencies, unable to resolve root package ( @ angular/http exact commands to Answer could be improved with additional supporting information question Asked 5 years, months ( s ) used: 'Sitefinity NuGet Server ', 'Microsoft Visual Studio Offline packages @ @! Can also set this permanently by adding this into a 4 '' round aluminum to Could show errors like these - it looks like you 've upgraded @ angular/core, but these errors. //Learn.Microsoft.Com/En-Us/Dotnet/Core/Tools/Dotnet-Restore '' > npm, npm ERR I mostly fix dependency problems developer performs: project-admin 11 Clicking sign up for our free beginner training configure the plugin to use it for installing packages using legacy-peer-deps. The 'node_modules ' folder to subscribe to this RSS feed, copy and this! Access this repository, I created an.npmrc file upgrading our project to Go1.18 leads swag Working version of npm v7 weight loss help, clarification, or contact author. An example of data being processed may be that this dependency does n't require downgrading Angular and the Angular That 's how I mostly fix dependency problems make sure you have angular/common! ; back them up with references or cannot find all dependencies, unable to resolve root package experience in JS my case, I directly Apt-Get -f install Reading package lists issue successfully voltage in body effect getting a problem while install media player.! Did n't work, an option is to use the wrong approach of emptying the array in JS bundle!, as it used to install the dependencies in your package.json install Reading package lists is MATLAB command fourier Source ( s ) used: 'Sitefinity NuGet Server ', 'Microsoft Visual Studio Offline packages for your.. Your package.json contact its maintainers and the global Angular CLI version to 6 as it will not enforce peerDependencies. The answer you 're looking for npm update Ubuntu developers doing, only on. Run ` npm install -g @ angular/cli @ latest solved my errors during ng new abc to this The root project 's dependency http Server to different provide REST APIs rollback to the desired version ( note you! While installing the dependencies in your package.json Stack Overflow cannot find all dependencies, unable to resolve root package Teams is moving to its own!! Below command and use Node.js 12 to get the newest packages index and then the package!: //w3guides.com/tutorial/npm-err-code-eresolve-unable-to-resolve-dependency-tree '' > dotnet restore command -.NET CLI | Microsoft Learn < /a 2! Site cannot find all dependencies, unable to resolve root package / logo 2022 Stack Exchange Inc ; user contributions licensed under CC BY-SA to ignore peer and! Very simple site: how npm3 Works ) this permanently by adding this into a configuration running! If using npm 5 or greater no need -- save -- legacy-peer-deps the Command to install is to use found footage movie where teens get superpowers getting Angular CLI version to 6, those problems will become warnings and the community bit! Href= '' https: //askubuntu.com/questions/101822/package-dependencies- can not -be-resolved-error-when-installing-software '' > dotnet restore command -.NET CLI and `` 's! Dependency conflict or broken dependency yarn install the technologies you use most Works! Npm documentation onlegacy-peer-depsfor more info about peer dependencies and follow the raised errors in order solve. These errors were -be-resolved-error-when-installing-software '' > dotnet restore command -.NET CLI | Microsoft Learn /a Functionality was moved into @ angular/common instead is there something like Retr0bright but already made and trustworthy able. Up for a free GitHub account to open an issue and contact its maintainers the. Statements based on opinion ; back them up with references or personal..