Command "yarn run build" exited with 1. Vercel deploy

Question

I've been trying to deploy my create-react-app to vercel but keep getting the following error. Everything works locally and even builds with no errors. How can I fix it? I already tried to get variables on vercel project settings and nothing.

I build with npm run build and do nothing with Yarn, so I don't get it.

    [1/4] Resolving packages...
    [2/4] Fetching packages...
    [3/4] Linking dependencies...
    warning " > @testing-library/user-event@12.8.3" has unmet peer dependency "@testing-library/dom@>=7.21.4".
    warning "react-scripts > tailwindcss@3.0.23" has unmet peer dependency "autoprefixer@^10.0.2".
    warning "react-scripts > eslint-config-react-app > eslint-plugin-flowtype@8.0.3" has unmet peer dependency "@babel/plugin-syntax-flow@^7.14.5".
    warning "react-scripts > eslint-config-react-app > eslint-plugin-flowtype@8.0.3" has unmet peer dependency "@babel/plugin-transform-react-jsx@^7.14.9".
    [4/4] Building fresh packages...
    Done in 74.94s.
    Running "yarn run build"
    yarn run v1.22.17
    $ react-scripts build
    Creating an optimized production build...
    Treating warnings as errors because process.env.CI = true.
    Most CI servers set it automatically.
    Failed to compile.
    src/App.tsx
      Line 4:9:   'BrowserRouter' is defined but never used  @typescript-eslint/no-unused-vars
      Line 4:24:  'Navigate' is defined but never used       @typescript-eslint/no-unused-vars
      Line 14:8:  'Login' is defined but never used          @typescript-eslint/no-unused-vars
    src/Components/Content/Message/Message.jsx
      Line 5:9:  'Navigate' is defined but never used  no-unused-vars
    src/Components/Content/Message/MessageInfo/MessageAccounts.jsx
      Line 9:13:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Content/Profile/Profile.jsx
      Line 34:13:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Content/Profile/ProfileInfo/PersonalData.jsx
      Line 10:17:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Content/Profile/ProfileInfo/Review.jsx
      Line 14:13:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
      Line 20:21:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Content/Users/Usersc.jsx
      Line 5:9:    'Navigate' is defined but never used                                                                       no-unused-vars
      Line 27:29:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Header/Header.jsx
      Line 4:9:    'NavLink' is defined but never used                                                                        no-unused-vars
      Line 26:25:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Header/HeaderContainer.tsx
      Line 15:13:  'axios' is assigned a value but never used  @typescript-eslint/no-unused-vars
    src/Components/Redux/auth-reducer.ts
      Line 69:50:  Array.prototype.filter() expects a return value from arrow function  array-callback-return
    src/Components/Redux/userspage-reducer.ts
      Line 1:9:     'HeaderAPI' is defined but never used  @typescript-eslint/no-unused-vars
      Line 66:130:  Expected '!==' and instead saw '!='    eqeqeq
    src/Components/Sidebar/Friends/FriendAccount.jsx
      Line 9:13:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    src/Components/Sidebar/Friends/Friends.jsx
      Line 6:64:  Array.prototype.map() expects a value to be returned at the end of arrow function  array-callback-return
    src/common/Loading/loading.jsx
      Line 7:9:  img elements must have an alt prop, either with meaningful text, or an empty string for decorative images  jsx-a11y/alt-text
    error Command failed with exit code 1.
    info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.
    Error: Command "yarn run build" exited with 1`

is't my package.json:

{
  "homepage": "https://yefimchuk.github.io/social-network-React",
  "name": "first-react-app",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@testing-library/jest-dom": "^5.11.4",
    "@testing-library/react": "^11.1.0",
    "@testing-library/user-event": "^12.1.10",
    "antd": "^4.18.7",
    "axios": "^0.25.0",
    "react": "^17.0.2",
    "react-dom": "^17.0.2",
    "react-redux": "^7.2.6",
    "react-router": "^6.2.1",
    "react-router-dom": "^6.2.2",
    "react-scripts": "^5.0.0",
    "redux": "^4.1.2",
    "redux-thunk": "^2.4.1",
    "typescript": "^4.5.4",
    "web-vitals": "^1.0.1"
  },
  "scripts": {
    "predeploy": "npm run build",
    "deploy": "gh-pages -d build",
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": [
      "react-app",
      "react-app/jest"
    ]
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version",
      "last 1 firefox version",
      "last 1 safari version"
    ]
  },
  "devDependencies": {
    "gh-pages": "^3.2.3"
  }
}

can anyone help? what is mean and how is't solve?

Answer 1

The answer is in the log:

Treating warnings as errors because process.env.CI = true.
Most CI servers set it automatically.

Because you're in a CI environment, all ESLint warnings (about code style and stuff) are treated as actual errors, resulting in this:

Failed to compile.

You can temporarily disable ESLint, or just fix all warnings described in the log.