Unexpected identifier with jest + vuejs + vuetify

Question

I've searched high and low for an answer. I suspect that it is a .babelrc issue, but I can't find an answer that works.

The app runs just fine, but as I found out, both Jest and Rollup really depend on .babelrc. The other possible culprit is Leaflet. Of all the components that I build and test, only the one containing Leaflet and vue2-leaflet seem to have this problem. Considering I'm working on a mapping app, this is critical for me.

I'm posting here, because I can't prove anything. And there are a number of other folks that have seen similar problems.

Terminal Output:

nr test:unit

> [email protected] test:unit /Users/dan.mahoney/Projects/cxl-vue-leaflet
> NODE_ENV=testing BABEL_DISABLE_CACHE=1 jest --verbose --no-cache

Determining test suites to run...

# Starting...
# 1 test suites found.

#  FAIL  src/components/__test__/specs/cxl-vue-leaflet.spec.js

#
#   /Users/dan.mahoney/Projects/cxl-vue-leaflet/node_modules/vuetify/lib/index.js:1
#
#   ({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import Vuetify from './components/Vuetify';
#                                                                                                   ^^^^^^^
#
#   SyntaxError: Unexpected identifier
#
#   Stack:
#
#       at new Script (vm.js:85:7)

1..0

# Test Suites:  0%            , 1 failed, 1 total
# Tests:       0 total
# Time:        2.088s

# Ran all test suites.

npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! [email protected] test:unit: `NODE_ENV=testing BABEL_DISABLE_CACHE=1 jest --verbose --no-cache`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] test:unit script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/dan.mahoney/.npm/_logs/2019-03-08T21_06_53_748Z-debug.log

.babelrc:

{
  "sourceMaps": true,
  "presets": [
    [
      "@babel/preset-env",
    ]
  ],
  "env": {
    "test": {
      "presets": [
        [
          "env",
          {
            "targets": {
              "node": "current"
            }
          }
        ]
      ]
    }
  },
  "plugins": [
      "transform-es2015-modules-commonjs",
      ["add-module-exports", {
        "vuetify": {
          "transform": "vuetify/es5/components/${member}",
          "preventFullImport": "false"
        },
      }],
  ]
}

Jest config in package.json:

"jest": {
    "transformIgnorePatterns": [
      "<rootDir>/node_modules/"
    ],
    "moduleFileExtensions": [
      "js",
      "vue"
    ],
    "moduleNameMapper": {
      "^@/(.*)$": "<rootDir>/src/$1",
      "^.+\\.(css)$": "identity-obj-proxy"
    },
    "transform": {
      "^.+\\.js$": "<rootDir>/node_modules/babel-jest",
      "^.+\\.vue$": "vue-jest",
      ".+\\.(css|styl|less|sass|scss|png|jpg|ttf|woff|woff2)$": "jest-transform-stub"
    },
    "reporters": [
      "jest-tap-reporter"
    ],
    "collectCoverageFrom": [
      "**/components/*.vue",
      "!**/node_modules/**"
    ]
  },

Dependencies:

"dependencies": {
    "get-value": "^3.0.1",
    "leaflet": "^1.4.0",
    "leaflet.icon.glyph": "^0.2.0",
    "moment": "^2.23.0",
    "vue-moment": "^4.0.0",
    "vue2-leaflet": "^2.0.2",
    "vue2-leaflet-markercluster": "^3.0.0",
    "vuetify": "^1.5.5"
  },
  "devDependencies": {
    "@babel/core": "^7.3.4",
    "@babel/plugin-proposal-object-rest-spread": "^7.3.4",
    "@babel/plugin-transform-runtime": "^7.3.4",
    "@babel/preset-env": "^7.3.4",
    "@vue/cli-service": "^3.5.0",
    "@vue/test-utils": "^1.0.0-beta.28",
    "babel-core": "^7.0.0-bridge.0",
    "babel-eslint": "^10.0.1",
    "babel-jest": "^24.3.1",
    "babel-plugin-add-module-exports": "^1.0.0",
    "babel-plugin-external-helpers": "^6.22.0",
    "babel-plugin-source-map-support": "^2.0.1",
    "babel-plugin-transform-es2015-modules-commonjs": "^6.26.2",
    "babel-plugin-transform-imports": "^1.4.1",
    "babel-plugin-transform-object-rest-spread": "^6.26.0",
    "chromedriver": "^2.38.3",
    "eslint": "^5.15.1",
    "eslint-config-airbnb-base": "^13.1.0",
    "eslint-config-standard": "^12.0.0",
    "eslint-config-strict": "^14.0.1",
    "eslint-config-strict-es": "^1.0.4",
    "eslint-detailed-reporter": "^0.7.3",
    "eslint-import-resolver-webpack": "^0.11.0",
    "eslint-loader": "^2.1.0",
    "eslint-plugin-html": "^5.0.0",
    "eslint-plugin-import": "^2.14.0",
    "eslint-plugin-jest": "^22.1.3",
    "eslint-plugin-leon-require-jsdoc": "0.0.1",
    "eslint-plugin-node": "^8.0.1",
    "eslint-plugin-promise": "^4.0.1",
    "eslint-plugin-security": "^1.4.0",
    "eslint-plugin-standard": "^4.0.0",
    "eslint-plugin-vue": "^5.1.0",
    "eslint-plugin-vue-a11y": "0.0.28",
    "growl": "^1.10.2",
    "husky": "^1.3.1",
    "identity-obj-proxy": "^3.0.0",
    "is-image": "^2.0.0",
    "jest": "^24.3.1",
    "jest-tap-reporter": "^1.9.0",
    "jest-transform-stub": "^2.0.0",
    "jest-vue-preprocessor": "^1.5.0",
    "jsdoc": "^3.5.5",
    "jsdoc-vue": "^1.0.0",
    "jsdom": "^13.0.0",
    "jsdom-global": "^3.0.2",
    "material-design-icons-iconfont": "^4.0.2",
    "minimist": "^1.2.0",
    "nightwatch": "^1.0.11",
    "npm-merge-driver": "^2.3.5",
    "parse5": "^5.1.0",
    "raf": "^3.4.0",
    "require-extension-hooks": "^0.3.2",
    "require-extension-hooks-babel": "^0.1.1",
    "require-extension-hooks-vue": "^2.0.0",
    "rollup": "^1.6.0",
    "rollup-plugin-analyzer": "^3.0.0",
    "rollup-plugin-babel": "^4.3.0",
    "rollup-plugin-babel-minify": "^7.0.0",
    "rollup-plugin-commonjs": "^9.1.8",
    "rollup-plugin-postcss": "^2.0.1",
    "rollup-plugin-replace": "^2.1.0",
    "rollup-plugin-vue": "^4.3.2",
    "selenium": "^2.20.0",
    "stylus": "^0.54.5",
    "stylus-loader": "^3.0.1",
    "tap-summary": "^4.0.0",
    "vue": "^2.6.8",
    "vue-jest": "^3.0.4",
    "vue-loader": "^15.7.0",
    "vue-meta": "^1.5.8",
    "vue-template-compiler": "^2.6.8",
    "vuepress": "^1.0.0-alpha.42",
    "vuepress-jsdoc": "^1.0.3",
    "vuetify-loader": "^1.0.8"
  },

I'm really at a loss here. Thanks for any help.

Answer 1

By default, Jest doesn't transform anything in node_modules (where vuetify package lives), but you actually need it to run vuetify through the configured babel-jest transform so that the imports could be transpiled. To do that, use this config in jest.config.js:

module.exports = {
  transformIgnorePatterns: [
    '<rootDir>/node_modules/(?!vuetify)'
  ],
  ...
}

A Pull Request was just submitted to document this pitfall.