GDG Lightning Talk 2020.06.11 Class Free code see comments for presentation link

classFreeSample.js

/**
 * 'class free' object constructor for a simple counter that counts up or down
 *
 * @param {Object} Spec - generic object for member destructuring-assignments
 * @param {String} Spec.runBy - name of person using the constructor
 * @returns {{up: Function, down: Function, toJSON: Function}}
 */
function counter_constructor(Spec) {
    let {
        runBy = 'John Doe', // default value if not specified
        counter = 0, // initialize private member of state not expected in Spec
        forgotToSay // no default; if not specified gets undefined
    } = Spec;

    /**
     * private function that prints a greeting to the runBy member passed in by
     * Spec obj or set to default value if not passed
     */
    const sayHello = () => (console.log(`Hello, ${runBy}. Let's count!`));

    /**
     * Increases state counter by one
     * @returns {boolean}
     */
    const up = () => {
        counter += 1;
        return true;
    };

    /**
     * Decreases state counter by one
     * @returns {boolean}
     */
    const down = function () {
        counter -= 1;
        return true;
    }

    /**
     * This returns an object of selected members and can be called directly or
     * using JSON.stringify on an Object made with a  _constructor
     * (not using new keyword)
     *
     * @returns {Object} Snapshot - selected items for logging or debugging
     */
    const toJSON = function () {
        let Snapshot = {
            title: `a selective snapshot of ${counter_constructor.name}`,
            Spec,
            runBy,
            forgotToSay,
            counter,
            up,
            down,
            toJSON
        };
        return Object.freeze(Snapshot);
    };

    sayHello();

    return Object.freeze({
        up,
        down,
        toJSON,
    });
}

const Count = counter_constructor({runBy: "rudy"});
Count.up();
Count.up();
Count.up();
Count.down();
console.log('---');
console.log(Count.up());
console.log(Count.down());
console.log('---');
console.log(Count);
console.log('---');
console.log(Count.toJSON());
console.log('---');
console.log(JSON.stringify(Count, null, 4));

My IDE is WebStorm from JetBrains, I have submitted this issue "Invalid Quick Doc for properties when JSDoc record type is used" and it has been accepted.

In our example, in my IDE, autocomplete works for Count.method but the pop up doc falls back to the constructor and not the JSDOC inside the constructor for shared methods.

I will do some research on if there's a better way to document the @returns also. This is where I'm at for now.