“解析错误：保留关键字'import'”

Question

In Visual Studio Code I get Parsing error: The keyword 'import' is reserved .

What actions would fix this error?

0. A minimal, complete and verifiable example

I provide my .eslintrc.json and package.json files in Section 2 below.
However, they will likely not be sufficient to reproduce the error.
So here is a link to a zip file containing all the necessary project files .

To locally install the project, run npm install . – This may take about 5-9 minutes. ¹
Then npm start should open the project in the default web browser. ²

When I do this and hit F12 , I get no errors but two warnings in the console of the browser.

The warnings are in line with the rules in .eslintrc.json (Section 2 below) :

• 'unUsedArgument' is defined but never used. Allowed unused args must match /^_/u no-unused-vars 'unUsedArgument' is defined but never used. Allowed unused args must match /^_/u no-unused-vars , and

• 'unUsedVariable' is assigned a value but never used. Allowed unused vars must match /^_/u no-unused-vars 'unUsedVariable' is assigned a value but never used. Allowed unused vars must match /^_/u no-unused-vars .

1. Parsing error: The keyword 'import' is reserved

The error in the title has nothing to do with my choice of text editor.
This is easily confirmed by running ESLint from the command line.

npx eslint src

2. Configuration files of my reproducible example

package.json :

{
  "name": "parsing-error",
  "version": "0.1.0",
  "dependencies": {
    "@testing-library/jest-dom": "^4.2.4",
    "@testing-library/react": "^9.4.1",
    "@testing-library/user-event": "^7.2.1",
    "react": "^17.0.2",
    "react-dom": "^17.0.2",
    "react-scripts": "4.0.3"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app"
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version"
    ]
  }
}

.eslintrc.json :

{
  "rules": {
    "no-unused-vars": [
      "warn",
      {
        "argsIgnorePattern": "^_",
        "varsIgnorePattern": "^_"
      }
    ]
  }
}

3. Visual Studio Code? – Other text editors or IDE:s?

The error, Parsing error: The keyword 'import' is reserved , also shows up when I open App.js in VS Code.

Although I am using Visual Studio Code, I invite answers (and discussions) of other text editors and IDE:s as well. Note that – in addition to installing ESLint correctly via npm – you also have to install a plugin/extension for your specific integrated development environment (IDE).
In my case, I use the official VS Code ESLint extension . ³

Still, the focus here should clearly be on what npm packages have been installed.

4. Is this question a duplicate?

I have been asked : is my question here a duplicate of
Parsing Error The Keyword import is Reserved (SublimeLinter-contrib-eslint) ?

I believe my question is not a duplicate of that question.

The origin of the package.json of my question comes from a Create React App via the command
npx create-react-app <the-name-of-my-app> .

The package.json of the other question is missing the react-scripts npm package which every Create React App must have. The other question is clearly not about Create React App , whereas my question is . ⁴

4a. How is ESLint integrated into Create React App?

As this answer explains, a Create React App depends directly on the react-scripts package.

The react-scripts package in turn depends on the eslint-config-react-app package (and on many other packages), which in turn depends on the @babel/eslint-parser package. I will come back to the latter dependency in the next subsection.

4b. Do any of the answers of the other question solve my question?

In the Community FAQ index for Stack Overflow there is a link to what I can do when I think my question is not a duplicate , which in turn links to another post that (implicitly) defines when a question is a duplicate of another question .

In summary, the key criterion for if a question is a duplicate is if any of the answers to the other question provides a solution to my own question.

So the key question is if there is such an answer .

First of all, the highest voted answer is obsolete in that it suggests to install the deprecated babel-eslint package . The authors of that package explicitly instruct to use the successor package @babel/eslint-parser instead of babel-eslint .

Installing the deprecated babel-eslint package would be even more problematic in my Create React App example, since @babel/eslint-parser is already installed (via eslint-config-react-app ). I cannot accept a proposed solution that simultaneously installs two different versions of the ESLint Parser (of which one is deprecated). So the highest voted answer is not an acceptable answer to the the question I ask here.

The accepted answer is not relevant in my case, as I installed ESLint only locally (not globally).

For all the other answers I tried the suggested solutions on my reproducible example, one by one. Most of them resulted in a different error message than mine, but none of them solved my question – contrary to the two self-answers I have posted below.

4c. Concluding remarks

Although the error messages are identical in the two questions – the reasons for why they occur are obviously significantly different. I conclude that my question is not a duplicate of Parsing Error The Keyword import is Reserved (SublimeLinter-contrib-eslint) .

5. Other reports of the error

References 18-24 of the list below are links to previous reports of the error – or similar errors.
Some of those links (questions) are likely related to the issue here, but possibly not all of them.

References

• The meaning of MCVE – a minimal, complete and verifiable example
• Zip file containing the needed project files
• Installing ESLint globally rather than locally (using npm install eslint --global )
  is not recommended
• VS Code ESLint extension
• In VS Code, add "eslint.nodePath": "C:\\Program Files\\nodejs", to settings.json
• Parsing Error The Keyword import is Reserved (SublimeLinter-contrib-eslint)
• Create React App
• The react-scripts npm package
• How is ESLint integrated into Create React App?
• eslint-config-react-app
• @babel/eslint-parser
• The Community FAQ index for Stack Overflow
• What can I do when I think my question's not a duplicate?
• A post that (implicitly) defines when a question is a duplicate of another question
• The highest voted answer of other question
• The deprecated babel-eslint package
• Installing ESLint globally might be a bad idea
• Parsing error: The keyword 'export' is reserved
• Parsing error: The keyword 'import' is reserved
• ERROR: Parsing Error: The keyword 'const' is reserved
• eslint: error Parsing error: The keyword 'const' is reserved
• Setting up Airbnb ESLint with React and Webpack
• Parsing error: The keyword 'enum' is reserved
• ESLint Parsing error: Unexpected token

---

^{1 Since it is recommended to install ESLint locally , I assume all readers here do so.}

^{2 In my case Google Chrome Version 98.0.4758.102, 64-bit. Running on Windows 10.}

^{3 Apart from installing the extension, I have added "eslint.nodePath": "C:\\Program Files\\nodejs", to my (user) settings.json file in VS Code. No other changes.}

^{4 I have added the create-react-app tag to my question.}

Answer 1

Here is a simple solution – just move the rules attribute from .eslintrc.json to the eslintConfig attribute of package.json . ¹

And don't keep .eslintrc.json . Just delete it! ²

The package.json file will now be as follows.

package.json :

{
  "name": "parsing-error",
  "version": "0.1.0",
  "dependencies": {
    "@testing-library/jest-dom": "^4.2.4",
    "@testing-library/react": "^9.4.1",
    "@testing-library/user-event": "^7.2.1",
    "react": "^17.0.2",
    "react-dom": "^17.0.2",
    "react-scripts": "4.0.3"
  },
  "scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test",
    "eject": "react-scripts eject"
  },
  "eslintConfig": {
    "extends": "react-app",
    "rules": {
      "no-unused-vars": [
        "warn",
        {
          "argsIgnorePattern": "^_",
          "varsIgnorePattern": "^_"
        }
      ]
    }
  },
  "browserslist": {
    "production": [
      ">0.2%",
      "not dead",
      "not op_mini all"
    ],
    "development": [
      "last 1 chrome version"
    ]
  }
}

That's it! ³

Check to see that you were successful :

npx eslint . --ext .js

Expect to see :

No error. – Yay!

If your text editor (VS Code in my case) is still open, make sure that you restart it before you expect to see the error go away!

References

• A more cumbersome solution to the question asked
• Suggesting to have ESLint rules in package.json under eslintConfig
• Installation of ESLint using npm
• ESLint gets installed even though it isn't explicitly mentioned in package.json | Section 1

---

^{1 I got the idea from this post .}

^{2 Don't run npm init @eslint/config either. The error(s) will persevere if you don't delete .eslintrc.json !}

^{3 A. If you suspect that you may have a global installation of ESLint, first run:
npm uninstall eslint --global}

^{B. If you have already run npm install – as suggested on line 7 of the question – then you shouldn't need to run npm install eslint --save-dev to install ESLint.
The reason is that having react-scripts in package.json means that ESLint gets installed by npm install .
Section 1 of this answer tells us that ESLint is in the dependency tree of react-scripts .}

Answer 2

0. Prerequisites

If the server is running, close it by hitting Ctrl + C .

I strongly recommend uninstalling any global installations of ESLint.
To see what global packages are installed, in the command line run: ¹

npm list --global --depth 0

If ESLint is globally installed, uninstall by running:

npm uninstall eslint --global

To correctly install ESLint into your local project, I recommend performing the following two steps.

1. Locally install ESLint.

2. Create a functioning .eslintrc.json file.

As it turns out, you will also need to do a third step.

3. Update all npm packages to their latest versions.

1. Locally install ESLint

To locally install ESLint, run: ²

npm install eslint --save-dev

This will add

  ,
  "devDependencies": {
    "eslint": "^7.32.0"
  }

at the end of package.json .

2. Create a .eslintrc.json file that works

NOTE! Before moving on, do yourself a favor by saving a copy of your current .eslintrc.json file, as the next command will destroy (recreate) that file.

To create a new .eslintrc.json file, run:

npm init @eslint/config

You will be asked a number of questions, to which I answer by pressing Enter to choose the default, except for the format which I choose to be JSON (instead of JavaScript ).

In addition to creating the .eslintrc.json file, this will also add the "eslint-plugin-react": "^7.29.2" attribute under devDependencies to the package.json file. ³

The command npm init @eslint/config destroys the existing .eslintrc.json file, so you will have to manually add back any "rules" or other JSON settings that you want to keep.
In this case, I add back the rules that were in the original .eslintrc.json .
The result is as below.

.eslintrc.json :

{
  "env": {
    "browser": true,
    "es2021": true
  },
  "extends": [
    "eslint:recommended",
    "plugin:react/recommended"
  ],
  "parserOptions": {
    "ecmaFeatures": {
      "jsx": true
    },
    "ecmaVersion": "latest",
    "sourceType": "module"
  },
  "plugins": [
    "react"
  ],
  "rules": {
    "no-unused-vars": [
      "warn",
      {
        "argsIgnorePattern": "^_",
        "varsIgnorePattern": "^_"
      }
    ]
  }
}

Now when I open VS Code, instead of an error there are two warnings, which is exactly the desired outcome.

Great! But wait – unfortunately there turns out to be a fly in the ointment. The problem is that, when I now run npm start to open the project in the web browser and hit F12 , two errors show up in the console.
The error messages are:

• Uncaught ReferenceError: process is not defined , and
• Line 0: Parsing error: ImportDeclaration should appear when the mode is ES6 and in the module context .

Luckily, I have already posted a solution to this problem, namely:
Update all npm packages to their latest versions .
The section below is a bit succinct, so if you want more flesh on the bones, go visit that other answer .

Update all npm packages to their latest versions

Consider updating all npm packages to their latest versions.
The purpose is to decrease the risk of getting version conflicts.
The advice to update all packages has also been put forth in this answer .

A. Globally install npm-check-updates

In the command line, run:

npm install --global npm-check-updates

B. Update package.json to contain the latest versions

The following command will write the latest package version numbers to your package.json :

npm-check-updates --upgrade

Here is what it looks like in Windows 10:

C. Install the latest versions

In the command line, run:

npm install

D. Check for errors in the browser and/or in the terminal

In the command line, run:

npm start

Both the browser and the terminal now displays five errors .

Discomforting, eh?

Yes definitely! – But don't give up hope! Just close the server ( Ctrl + C ) and try it over and over again.
Yesterday when I got these errors, all I needed to do was to run npm start one more time.
Today I tried running npm start 4-5 more times, but still got the errors.
So I tried npm install && npm start twice, and finally it ran without errors.
Not sure what is going on. Maybe some time has to pass before it works?

Finally there are no errors in the browser.

And the terminal says Compiled successfully!

Yay! ⁴

Conclusion

Following the steps above helped me remedy the error in the question title:
Parsing error: The keyword 'import' is reserved .

For a project with settings even slightly different, ⁵ just copy-pasting from the .eslintrc.json file above is unlikely to work.
Running npm init @eslint/config and upgrading all packages is more likely to be successful.

References

• npm – get a list of globally installed packages
• Installation of ESLint using npm
• Start using @eslint/config in your project
• When should I use @babel/eslint-parser ?
• Update all npm packages to their latest versions
• Update all current packages to their lastest versions
• npm-check-updates – documentation

---

¹ I am on Windows 10, but I expect all the commands provided here to work just as fine on both Linux and macOS.

² A. Expect this command to take about 5-10 minutes to complete.
B. As long as your source code is not transformed by Babel, there is no reason to install @babel/eslint-parser . Just normal eslint should be enough. See When should I use @babel/eslint-parser ?
If you are using TypeScript, then you will need @babel/eslint-parser .
The command to install is:
npm install eslint @babel/core @babel/eslint-parser --save-dev
The npm init @eslint/config configuration command should be used in the same way as for the normal ( non -@babel) ESLint.

³ The "eslint-plugin-react" attribute in package.json does not seem to be of much relevance though.

⁴ The two warnings still show up in the text editor – just as they should.

⁵ For example, you might be using Angular or Vue instead of React.