How can I turn off ESLint's no-restricted-syntax rule just for ForOfStatement?

Question

I am using ESLint for my ES6 program, with the AirBNB rule-set. For good and adequate reasons, I am using the for...of construction in my code, but ESLint objects to it, issuing a no-restricted-syntax error.

The documentation at http://eslint.org/docs/rules/no-restricted-syntax explains how I can specify in my .eslint file the set of syntax-tree nodes that it objects to: for example, if all I dislike is the with statement, I can use:

"no-restricted-syntax": ["warn", "WithStatement"]

But I don't want to specify a whole set of unapproved constructions, I just want to say that I consider one such construction OK. Something conceptually similar to

ESlint.rules['no-restricted-syntax'].removeEntry('ForOfStatement');

Is there a way to do this in the ESLint file? Or, failing that, is there at least a way to get it to tell me what its current no-restricted-syntax configuration is, so I can manually remove ForOfStatement from it?

Haematic

a shortcut, not the best answer is using the disabling eslint rules with comments for blocks or lines or files. – Neolith

If you have installed the airbnb ruleset, you can surely look it up in the respective configuration file? – Zina

Thanks, amir. I know how to tell ESLint "ignore this line" or "ignore this rule for this line": I want to be more ambitious, and teach ESLint that I consider the use of for...of always OK. – Haematic

for those like me, who arrive here via google search, here's a good discussion about why the syntax is restricted in the first place: github.com/airbnb/javascript/issues/1271 – Sketchy

Answer 1

You can, but only if you use a JS config file.

In the old config system (.eslintrc.js):

const styleConfig = require('eslint-config-airbnb-base/rules/style');
const [_severity, ...restrictedSyntax] = styleConfig.rules['no-restricted-syntax'];

In the new flat config (eslint.config.js):

const compat = new FlatCompat({
  baseDirectory: __dirname,
  recommendedConfig: js.configs.recommended,
});

const airbnb = compat.extends('airbnb');
const [_severity, ...restrictedSyntax] = airbnb.find(c => c.rules?.['no-restricted-syntax']);

And then manipulate the restrictedSyntax variable as desired.

Economics

Answer 2

Check existing config

Based on the current master branch, eslint-config-airbnb currently disables four syntax forms:

1. ForInStatement
2. ForOfStatement
3. LabeledStatement
4. WithStatement

You can verify this or see if there are any differences by using ESLint's --print-config CLI flag:

$ eslint --print-config file.js

ESLint will print out the config it would use to lint file.js, and you can find the config for the no-restricted-syntax rule there.

Override no-restricted-syntax

If you want to override Airbnb's preset, you can do so in the rules section of your .eslintrc.json file:

{
    "rules": {
        "no-restricted-syntax": ["error", "ForInStatement", "LabeledStatement", "WithStatement"]
    }
}

There's no way to configure the rule to use the no-restricted-syntax config inherited from Airbnb's preset excepting only a single syntax form.

Bautram

Thanks, btmills. The bit of a puzzle I was missing was --print-config, which at least allows me to hand-craft an .eslint rule configuration that makes minimal changes to what I inherited. – Haematic

It's a shame there is no way to have .eslintrc modify and existing rule configuration rather then replacing it; but since that's how it is, your answer tells me all there is to know. I will Accept it as soon as I find the right button! – Haematic

How can I enable ForInStatement and ForOfStatement? – Tonatonal

@Tonatonal same as above except use ["error", "LabeledStatement", "WithStatement"] – Lewie

Answer 3

Add the below lines of code to restrict this error in your application in .eslintrc.js file

module.exports = {
  extends: ['airbnb-base', 'plugin:prettier/recommended'],
  plugins: ['no-only-tests'],
  rules: {
    'no-only-tests/no-only-tests': 2,
    "no-restricted-syntax": ["error", "ForInStatement", "LabeledStatement", "WithStatement"]
  },
};

Pragmatism