Standards .eslintrc.js

.eslintrc.js

module.exports = {
  env: {
    es6: true,
    node: true
  },
  plugins: ["prettier"],
  extends: ["plugin:prettier/recommended"],
  parserOptions: {
    sourceType: "module"
  },
  rules: {
    "no-console": 0,
    "no-unused-vars": [2, { argsIgnorePattern: "^_" }],
    "prettier/prettier": "error"
  }
};

eslint-jest.spec.js

// Gratefully stolen from https://robots.thoughtbot.com/testing-your-style-with-eslint-and-mocha
// For testing with Jest
const glob = require("glob");
const { CLIEngine } = require("eslint");

const paths = glob.sync("./+(src|__tests__)/**/*.js");
const engine = new CLIEngine({
  envs: ["node", "jest"],
  useEslintrc: true
});

const results = engine.executeOnFiles(paths).results;

describe("ESLint", function() {
  results.forEach(result => generateTest(result));
});

function generateTest(result) {
  const { filePath, messages } = result;

  it(`validates ${filePath}`, function() {
    expect(formatMessages(messages)).toBe(`\n`);
  });
}

function formatMessages(messages) {
  const errors = messages.map(message => {
    return `${message.line}:${message.column} ${message.message.slice(
      0,
      -1
    )} - ${message.ruleId}\n`;
  });

  return `\n${errors.join("")}`;
}

eslint-mocha.spec.js

// Gratefully stolen from https://robots.thoughtbot.com/testing-your-style-with-eslint-and-mocha
// For testing with Mocha
const glob = require("glob");
const { CLIEngine } = require("eslint");
const { assert } = require("chai");

const paths = glob.sync("./+(src|test)/**/*.js");
const engine = new CLIEngine({
  envs: ["node", "mocha"],
  useEslintrc: true
});

const results = engine.executeOnFiles(paths).results;

describe("ESLint", function() {
  results.forEach(result => generateTest(result));
});

function generateTest(result) {
  const { filePath, messages } = result;

  it(`validates ${filePath}`, function() {
    if (messages.length > 0) {
      assert.fail(false, true, formatMessages(messages));
    }
  });
}

function formatMessages(messages) {
  const errors = messages.map(message => {
    return `${message.line}:${message.column} ${message.message.slice(
      0,
      -1
    )} - ${message.ruleId}\n`;
  });

  return `\n${errors.join("")}`;
}