config-ops.js

/**
 * @fileoverview Config file operations. This file must be usable in the browser,
 * so no Node-specific code can be here.
 * @author Nicholas C. Zakas
 */
"use strict";

//------------------------------------------------------------------------------
// Private
//------------------------------------------------------------------------------

const RULE_SEVERITY_STRINGS = ["off", "warn", "error"],
    RULE_SEVERITY = RULE_SEVERITY_STRINGS.reduce((map, value, index) => {
        map[value] = index;
        return map;
    }, {}),
    VALID_SEVERITIES = [0, 1, 2, "off", "warn", "error"];

//------------------------------------------------------------------------------
// Public Interface
//------------------------------------------------------------------------------

module.exports = {

    /**
     * Normalizes the severity value of a rule's configuration to a number
     * @param {(number|string|[number, ...*]|[string, ...*])} ruleConfig A rule's configuration value, generally
     * received from the user. A valid config value is either 0, 1, 2, the string "off" (treated the same as 0),
     * the string "warn" (treated the same as 1), the string "error" (treated the same as 2), or an array
     * whose first element is one of the above values. Strings are matched case-insensitively.
     * @returns {(0|1|2)} The numeric severity value if the config value was valid, otherwise 0.
     */
    getRuleSeverity(ruleConfig) {
        const severityValue = Array.isArray(ruleConfig) ? ruleConfig[0] : ruleConfig;

        if (severityValue === 0 || severityValue === 1 || severityValue === 2) {
            return severityValue;
        }

        if (typeof severityValue === "string") {
            return RULE_SEVERITY[severityValue.toLowerCase()] || 0;
        }

        return 0;
    },

    /**
     * Converts old-style severity settings (0, 1, 2) into new-style
     * severity settings (off, warn, error) for all rules. Assumption is that severity
     * values have already been validated as correct.
     * @param {Object} config The config object to normalize.
     * @returns {void}
     */
    normalizeToStrings(config) {

        if (config.rules) {
            Object.keys(config.rules).forEach(ruleId => {
                const ruleConfig = config.rules[ruleId];

                if (typeof ruleConfig === "number") {
                    config.rules[ruleId] = RULE_SEVERITY_STRINGS[ruleConfig] || RULE_SEVERITY_STRINGS[0];
                } else if (Array.isArray(ruleConfig) && typeof ruleConfig[0] === "number") {
                    ruleConfig[0] = RULE_SEVERITY_STRINGS[ruleConfig[0]] || RULE_SEVERITY_STRINGS[0];
                }
            });
        }
    },

    /**
     * Determines if the severity for the given rule configuration represents an error.