Finds ESLint rules which are declared as warnings but for which there are no issues, to be safely upgraded to error

find-warnings-to-upgrade.js

/* eslint-disable no-console */

/**
 * External dependencies
 */
const execSync = require( 'child_process' ).execSync;
const reduce = require( 'lodash/reduce' );

/**
 * Internal dependencies
 */
const rules = require( './.eslintrc' ).rules;

function getRuleLevel( config ) {
	if ( 'number' === typeof config ) {
		return config;
	}

	if ( Array.isArray( config ) ) {
		return config[ 0 ];
	}

	return 0;
}

reduce( rules, ( memo, config, rule ) => {
	if ( 1 !== getRuleLevel( config ) ) {
		return Promise.resolve();
	}

	return memo.then( () => {
		return new Promise( ( resolve ) => {
			try {
				execSync( './node_modules/.bin/eslint --quiet --ext .jsx,.js --rule \'' + rule + ': 2\' .' );
				console.log( 'NO ERROR: ' + rule );
			} catch ( error ) {
			} finally {
				resolve();
			}
		} );
	} );
}, Promise.resolve() ).then( () => {
	console.log( 'Done' );
} );