Component does no re-render!

[kovkev]

Of course this has been posted here over and over.

I really want to know.. How do I troubleshoot mobx? Where do I put breakpoints to inspect the flow on action -> observers -> observed-values -> component?

---

Intended outcome:

I am trying to add an object inside an array inside an object inside an array which is part of the mobx store. I expect the component observing the store to re-render.

Actual outcome:

The component does not re-render

I see that the context store object has updated

How to reproduce the issue:

It used to work! I do not know how to reproduce the issue. Please see what I ask about troubleshooting above.

Versions

package.json:

{
  "name": "penpalling_website",
  "version": "0.1.0",
  "private": true,
  "dependencies": {
    "@babel/core": "^7.17.2",
    "@babel/preset-env": "^7.16.11",
    "@babel/preset-flow": "^7.16.7",
    "@babel/preset-react": "^7.16.7",
    "@babel/preset-typescript": "^7.16.7",
    "@pmmmwh/react-refresh-webpack-plugin": "0.4.3",
    "@react-native-async-storage/async-storage": "^1.16.1",
    "@react-native-community/async-storage": "^1.12.1",
    "@react-native-picker/picker": "^1.16.8",
    "@stream-io/flat-list-mvcp": "^0.10.1",
    "@stripe/react-stripe-js": "^1.7.0",
    "@stripe/stripe-js": "^1.22.0",
    "@svgr/webpack": "5.5.0",
    "@testing-library/jest-dom": "^5.16.2",
    "@testing-library/react": "^11.1.0",
    "@testing-library/user-event": "^12.1.10",
    "@types/jest": "^26.0.24",
    "@types/node": "^16.11.24",
    "@types/react": "^17.0.39",
    "@types/react-dom": "^17.0.11",
    "@typescript-eslint/eslint-plugin": "^4.33.0",
    "@typescript-eslint/parser": "^4.33.0",
    "axios": "^0.21.4",
    "babel-eslint": "^10.1.0",
    "babel-jest": "^26.6.0",
    "babel-loader": "8.1.0",
    "babel-plugin-module-resolver": "^4.1.0",
    "babel-plugin-named-asset-import": "^0.3.8",
    "babel-plugin-polyfill-corejs3": "^0.5.2",
    "babel-preset-react-app": "^10.0.1",
    "babel-preset-react-native": "^4.0.1",
    "bfj": "^7.0.2",
    "camelcase": "^6.3.0",
    "case-sensitive-paths-webpack-plugin": "2.3.0",
    "css-loader": "^4.3.0",
    "dotenv": "8.2.0",
    "dotenv-expand": "5.1.0",
    "eslint": "^7.32.0",
    "eslint-config-react-app": "^6.0.0",
    "eslint-plugin-flowtype": "^5.10.0",
    "eslint-plugin-import": "^2.25.4",
    "eslint-plugin-jest": "^24.7.0",
    "eslint-plugin-jsx-a11y": "^6.5.1",
    "eslint-plugin-react": "^7.28.0",
    "eslint-plugin-react-hooks": "^4.3.0",
    "eslint-plugin-testing-library": "^3.10.2",
    "eslint-webpack-plugin": "^2.6.0",
    "execa": "^6.0.0",
    "file-loader": "6.1.1",
    "find-cache-dir": "^3.3.2",
    "framework7-react": "^6.3.16",
    "fs-extra": "^9.0.1",
    "geolib": "^3.3.3",
    "google-maps-react": "^2.0.6",
    "html-webpack-plugin": "4.5.0",
    "identity-obj-proxy": "3.0.0",
    "jest": "26.6.0",
    "jest-circus": "26.6.0",
    "jest-resolve": "26.6.0",
    "jest-watch-typeahead": "0.6.1",
    "less": "^4.1.2",
    "less-loader": "^10.2.0",
    "make-dir": "^3.1.0",
    "mini-css-extract-plugin": "0.11.3",
    "mobx": "^6.3.13",
    "mobx-persist": "^0.4.1",
    "mobx-persist-store": "^1.0.4",
    "mobx-react": "^7.2.1",
    "next": "^11.1.4",
    "nodemon": "^2.0.15",
    "optimize-css-assets-webpack-plugin": "5.0.4",
    "pnp-webpack-plugin": "1.6.4",
    "postcss-flexbugs-fixes": "4.2.1",
    "postcss-loader": "3.0.0",
    "postcss-normalize": "8.0.1",
    "postcss-preset-env": "6.7.0",
    "postcss-safe-parser": "5.0.2",
    "prompts": "2.4.0",
    "query-string": "^7.1.1",
    "rc-swipeout": "^2.0.11",
    "react": "^17.0.2",
    "react-app-polyfill": "^2.0.0",
    "react-dev-utils": "^11.0.3",
    "react-device-detect": "^2.1.2",
    "react-dom": "^17.0.2",
    "react-google-maps": "^9.4.5",
    "react-google-places-autocomplete": "^3.3.2",
    "react-hot-loader": "^4.13.0",
    "react-native-expo-viewport-units": "^0.0.8",
    "react-native-gesture-handler": "^1.10.3",
    "react-native-google-places-autocomplete": "^2.4.1",
    "react-native-maps": "^0.28.1",
    "react-native-swipeout": "^2.3.6",
    "react-native-web": "^0.17.5",
    "react-native-web-maps": "^0.3.0",
    "react-refresh": "^0.8.3",
    "react-router-dom": "^5.3.0",
    "request": "^2.88.2",
    "resolve": "1.18.1",
    "resolve-url-loader": "^3.1.4",
    "sass-loader": "^10.2.1",
    "seedrandom": "^3.0.5",
    "semver": "^7.3.2",
    "stripe": "^8.202.0",
    "style-loader": "^1.3.0",
    "styled-components": "^5.3.3",
    "terser-webpack-plugin": "4.2.3",
    "ts-pnp": "1.2.0",
    "typescript": "^4.5.5",
    "unique-names-generator": "^4.5.0",
    "url-loader": "4.1.1",
    "uuid": "^8.3.2",
    "watch": "^1.0.2",
    "web-vitals": "^1.0.1",
    "webpack": "4.44.2",
    "webpack-dev-server": "3.11.1",
    "webpack-manifest-plugin": "2.2.0",
    "workbox-webpack-plugin": "5.1.4"
  },
  "scripts": {
    "start": "node scripts/start.js",
    "start:dev": "webpack serve --mode development --config ./config/webpack.config.js --hot",
    "build": "node scripts/build.js",
    "test": "node scripts/test.js"
  },
  "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": {
    "babel-plugin-react-native-web": "^0.17.5",
    "webpack-cli": "^4.9.2"
  },
  "jest": {
    "roots": [
      "<rootDir>/src"
    ],
    "collectCoverageFrom": [
      "src/**/*.{js,jsx,ts,tsx}",
      "!src/**/*.d.ts"
    ],
    "setupFiles": [
      "react-app-polyfill/jsdom"
    ],
    "setupFilesAfterEnv": [
      "<rootDir>/src/setupTests.js"
    ],
    "testMatch": [
      "<rootDir>/src/**/__tests__/**/*.{js,jsx,ts,tsx}",
      "<rootDir>/src/**/*.{spec,test}.{js,jsx,ts,tsx}"
    ],
    "testEnvironment": "jsdom",
    "testRunner": "/home/ubuntu/pdev/tgkj/penpalling_website/node_modules/jest-circus/runner.js",
    "transform": {
      "^.+\\.(js|jsx|mjs|cjs|ts|tsx)$": "<rootDir>/config/jest/babelTransform.js",
      "^.+\\.css$": "<rootDir>/config/jest/cssTransform.js",
      "^(?!.*\\.(js|jsx|mjs|cjs|ts|tsx|css|json)$)": "<rootDir>/config/jest/fileTransform.js"
    },
    "transformIgnorePatterns": [
      "[/\\\\]node_modules[/\\\\].+\\.(js|jsx|mjs|cjs|ts|tsx)$",
      "^.+\\.module\\.(css|sass|scss)$"
    ],
    "modulePaths": [],
    "moduleNameMapper": {
      "^react-native$": "react-native-web",
      "^.+\\.module\\.(css|sass|scss)$": "identity-obj-proxy"
    },
    "moduleFileExtensions": [
      "web.js",
      "js",
      "web.ts",
      "ts",
      "web.tsx",
      "tsx",
      "json",
      "web.jsx",
      "jsx",
      "node"
    ],
    "watchPlugins": [
      "jest-watch-typeahead/filename",
      "jest-watch-typeahead/testname"
    ],
    "resetMocks": true
  },
  "babel": {
    "presets": [
      "react-app"
    ]
  }
}

[kovkev]

Just to add more information, this is a websocket's .onmessage() adding a record to the array. It's using an action to do so (a member arrow function of the store class)

[urugator]

Have you consulted https://mobx.js.org/analyzing-reactivity.html ?

Also highly suggest

configure({   
    computedRequiresReaction: true,
    reactionRequiresObservable: true,
    observableRequiresReaction: true,
})

https://mobx.js.org/configuration.html#linting-options

[kovkev]

Thanks for the reply.

I thought about the problem a little bit more. I moved the observer deeper on the direct component utilizing the parameters. It told me to use slice() for some sort()s I had. It works now!

[kubk]

@kovkev This ESLint rule may be helpful for you (to avoid such bugs in the future): https://github.com/mobxjs/mobx/tree/main/packages/eslint-plugin-mobx#mobxmissing-observer