Suggested order of module members in Node.js

suggested-order-of-module-members.js

// Import modules
const crypto = require('crypto');

/**
 * Sample module showing suggested order of declaration for module members in Node.js
 *
 * Suggested order:
 *   - Constants before Properties before Methods
 *   - Public before Private
 *
 * Usage for this module:
 *   const sampleModule = require('suggested-order-of-module-members.js');
 *   console.log(sampleModule.SGP, sampleModule.getUuid());
 *
 * @link https://gist.github.com/zionsg - suggested-order-of-module-members.js
 * @link See also SuggestedOrderOfClassMembers.php in https://gist.github.com/zionsg/5e21d79bea3d150dac5625ec84d94eed
 * @link https://jsdoc.app/ used for documentation
 * @returns {Object}
 */
module.exports = (function () {
    /** @type {Object} Self reference - all public properties/methods are stored here & returned as public interface. */
    const self = {};

    /** @type {string} UTC timezone. */
    const UTC = '+00:00';

    /** @type {int} Do not use `var` to declare variables. */
    let startTime = 0;

    /**
     * Singapore timezone
     *
     * @public
     * @type {string}
     */
    self.SGP = '+08:00';

    /**
     * Get UUID v4 string
     *
     * @public
     * @returns {string} E.g. '123e4567-e89b-12d3-a456-426614174000'.
     */
    self.getUuid = function () {
        return crypto.randomUUID();
    };

    /**
     * Get current timestamp in ISO 8601 format
     *
     * @private
     * @returns {string}
     */
    function getTimestamp() {
        return (new Date()).toISOString();
    }

    /**
     * Initialization
     *
     * Run at the end after all properties/methods have been declared instead
     * of creating a `function init()` which may be hard to find if this module
     * has many lines of code with the possibility of forgetting to run it.
     */
    (async function init() { // async in case need to use await
        startTime = Date.now();
    })();

    // Return public interface of IIFE (Immediately Invoked Function Expression)
    return self;
})();