.eslintrc.js

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// our principles:
// - only problems, no syntax/stylistic related rules (done by extending from "eslint-config-problems")
// - do not force new EcmaScript features
//     + warn instead of error for improvements like "prefer-template"
//     + ignore if they depend on the situation or can make readability harder like "prefer-arrow-callback" or "object-shorthand"

module.exports = {
    "extends": "problems",
    "env": {
        "node": true
    },
    "parserOptions": {
        "ecmaVersion": 2018
    },
    "plugins": [
        "mocha"
    ],
    "rules": {
        "prefer-arrow-callback": "off",
        "prefer-template": "off",
        "object-shorthand": "off",

        // console.* is wanted in OpenWhisk actions
        "no-console": ["off", {"allow": true}],

        "template-curly-spacing": ["warn", "never"],

        "no-else-return": "off",

        // mocha rules intended to catch common problems:
        // - tests marked with .only() is usually only during development
        // - tests with identical titles are confusing
        // - tests defined using () => {} notation do not have access to globals
        // - tests nested in tests is confusing
        // - empty tests point to incomplete code
        // - mocha allows for synch tests, async tests using 'done' callback,
        //   async tests using Promise. Combining callback and a return of some value
        //   indicates mixing up the test types
        // - multiple before/after hooks in a single test suite/test is confusing
        // - passing async functions to describe() is usually wrong, the individual tests
        //   can be async however
        "mocha/no-exclusive-tests": "error",
        "mocha/no-identical-title": "error",
        "mocha/no-mocha-arrows": "error",
        "mocha/no-nested-tests": "error",
        "mocha/no-pending-tests": "error",
        "mocha/no-return-and-callback": "error",
        "mocha/no-sibling-hooks": "error",
        "mocha/no-async-describe": "error",
        "indent": ["error", 4],
        "keyword-spacing": [2],

        "no-unused-vars": ["error", { "caughtErrors": "none" } ]
    }
};