Takes an eslint json file and pulls out the count of each error

Get Eslint Count by Error

// eslint -f json . > output.json

const data = require('./output.json');

const result = {};
const files = new Set();
data
    .filter(({ warningCount, errorCount }) => warningCount > 0 || errorCount > 0)
    .forEach(fileProps => {
        const { messages, filePath } = fileProps;
        messages.forEach(props => {
            const { ruleId } = props;
            if (ruleId === 'no-unused-vars') {
                files.add(filePath);
            }
            if (!result[ruleId]) {
                result[ruleId] = 1;
            } else {
                result[ruleId]++;
            }
        });
    });

console.log(result);
console.log('Files with issues', files.size);