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I'm trying to get started using ESLint from this tutorial: https://davidwalsh.name/eslint

I've copied the example file. When I run eslint uploader.js in its directory, nothing happens - there is a line break, and then the prompt returns. No output at all.

I've run it on a JSON file in the same directory, and used a Grunt task to run it on all JS files project wide. These return a few errors, but nothing near what I'm expecting.

When I run eslint on the command line, it acts as expected - returning arguments and options documentation. I've tried rebooting the instance, reinstalling ESLint, intentionally introducing egrigious errors into uploader.js, but nothing happens, much less the output displayed in the tutorial. Can someone help?

Ben
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  • Well, what output were you expecting? `eslint` is just a checker. – E_net4 Jan 06 '16 at 22:48
  • The tutorial is very specific as to which errors to expect - they provide a sample file and its output (the first image from the top, in "Real Life Example"). – Ben Jan 06 '16 at 22:50

2 Answers2

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Starting from version 1.0.0 of ESLint, all linting rules are turned off by default.

That tutorial was written before this version, which would have expected some errors to show up without a configuration file. The official website provides a migration guide. In your case, you may wish to extend your ".eslintrc" file with "eslint:recommended" throughout that tutorial (or simply include the intended rules manually). Here's the closest you can get from the previous versions, according to the guide:

{
    "extends": "eslint:recommended",
    "rules": {
        "no-alert": 2,
        "no-array-constructor": 2,
        "no-caller": 2,
        "no-catch-shadow": 2,
        "no-empty-label": 2,
        "no-eval": 2,
        "no-extend-native": 2,
        "no-extra-bind": 2,
        "no-implied-eval": 2,
        "no-iterator": 2,
        "no-label-var": 2,
        "no-labels": 2,
        "no-lone-blocks": 2,
        "no-loop-func": 2,
        "no-multi-spaces": 2,
        "no-multi-str": 2,
        "no-native-reassign": 2,
        "no-new": 2,
        "no-new-func": 2,
        "no-new-object": 2,
        "no-new-wrappers": 2,
        "no-octal-escape": 2,
        "no-process-exit": 2,
        "no-proto": 2,
        "no-return-assign": 2,
        "no-script-url": 2,
        "no-sequences": 2,
        "no-shadow": 2,
        "no-shadow-restricted-names": 2,
        "no-spaced-func": 2,
        "no-trailing-spaces": 2,
        "no-undef-init": 2,
        "no-underscore-dangle": 2,
        "no-unused-expressions": 2,
        "no-use-before-define": 2,
        "no-with": 2,
        "camelcase": 2,
        "comma-spacing": 2,
        "consistent-return": 2,
        "curly": [2, "all"],
        "dot-notation": [2, { "allowKeywords": true }],
        "eol-last": 2,
        "no-extra-parens": [2, "functions"],
        "eqeqeq": 2,
        "key-spacing": [2, { "beforeColon": false, "afterColon": true }],
        "new-cap": 2,
        "new-parens": 2,
        "quotes": [2, "double"],
        "semi": 2,
        "semi-spacing": [2, {"before": false, "after": true}],
        "space-infix-ops": 2,
        "space-return-throw-case": 2,
        "space-unary-ops": [2, { "words": true, "nonwords": false }],
        "strict": [2, "function"],
        "yoda": [2, "never"]
    }
}

Since version 3.0.0, ESLint will refuse to work without a configuration file, printing an error message instead. This will hopefully prevent people from running into this issue.

E_net4
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  • Yes! Small gotchas are the worst. Thanks! Surprising, since that tutorial is not even a year old... – Ben Jan 06 '16 at 23:01
  • Glad I could help. I honestly prefer the new behaviour, it's much less zealous. I've added the full .eslintrc according to the migration guide (as one can see, it's bloated with rules). – E_net4 Jan 06 '16 at 23:05
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I've expirienced the same problem (year 2023 btw). I installed eslint and when I type npx eslint app.js it returns empty result, just a new empty line. So, solution for me was:

  1. I checked globally installed eslint npm list -g

  2. Eslint was installed globally, and I didn't want that, so I deleted it npm uninstall -g eslint

  3. Then I checked that package.json was on place (If you don't have package.json, then create it npm init and hit enter several times)

  4. I reinstalled eslint npm init eslint@/config

  5. And the most important part: in .eslintrc.json (which will be created after installing eslint) you have to set rules (I took this solution from an answer E_net4). For example:

     {
     "extends": "eslint:recommended",
     "rules": {
         "no-alert": 2,
         "no-array-constructor": 2,
         "no-caller": 2,
         "no-catch-shadow": 2,
         "no-empty-label": 2,
         "no-eval": 2,
         "no-extend-native": 2,
         "no-extra-bind": 2,
         "no-implied-eval": 2,
         "no-iterator": 2,
         "no-label-var": 2,
         "no-labels": 2,
         "no-lone-blocks": 2,
         "no-loop-func": 2,
         "no-multi-spaces": 2,
         "no-multi-str": 2,
         "no-native-reassign": 2,
         "no-new": 2,
         "no-new-func": 2,
         "no-new-object": 2,
         "no-new-wrappers": 2,
         "no-octal-escape": 2,
         "no-process-exit": 2,
         "no-proto": 2,
         "no-return-assign": 2,
         "no-script-url": 2,
         "no-sequences": 2,
         "no-shadow": 2,
         "no-shadow-restricted-names": 2,
         "no-spaced-func": 2,
         "no-trailing-spaces": 2,
         "no-undef-init": 2,
         "no-underscore-dangle": 2,
         "no-unused-expressions": 2,
         "no-use-before-define": 2,
         "no-with": 2,
         "camelcase": 2,
         "comma-spacing": 2,
         "consistent-return": 2,
         "curly": [2, "all"],
         "dot-notation": [2, { "allowKeywords": true }],
         "eol-last": 2,
         "no-extra-parens": [2, "functions"],
         "eqeqeq": 2,
         "key-spacing": [2, { "beforeColon": false, "afterColon": true }],
         "new-cap": 2,
         "new-parens": 2,
         "quotes": [2, "double"],
         "semi": 2,
         "semi-spacing": [2, {"before": false, "after": true}],
         "space-infix-ops": 2,
         "space-return-throw-case": 2,
         "space-unary-ops": [2, { "words": true, "nonwords": false }],
         "strict": [2, "function"],
         "yoda": [2, "never"]
     }
 }

  6. And npx eslint app.js returned a bunch of errors in my code (as it suppose to work). But I decided to change rules to some "standardized rules" and installed airbnb rules (instructions here https://www.npmjs.com/package/eslint-config-airbnb)

Thanx E_net4 for the idea how to solve this.

Niko
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