Make several kinds of objects to see which is the best type for use with JSON. Includes pattern for making new "naked" objects that can be serialized as JSON.

json-map.ts

// An experiment in making several types of objects in order to see what is the best one for use with JSON.
// Object types created are:
//    - Object.create(null) - totally blank object, not even inheritance from Object (i.e., not even 
//      hasOwnProperty()). THIS IS PROBABLY THE WAY TO GO FOR MAKING JSON OBJECTS.
//    - new Object() - inherits all base capabilities and properties
//    - new Map() - can't be stringified to JSON

//-----------------------------------------------------------------------------------------------------------------
scribble("================ Object.create(null)");
let obj = Object.create(null);
obj["property A"] = "value A";
obj["property B"] = "value B";
for (const p in obj) {
    // Note that hasOwnProperty() does not exist on the blank object created with Object.create(null).
    // if (obj.hasOwnProperty(p))
        scribble(p.toString() + ' = ' + obj[p]);
}

//-----------------------------------------------------------------------------------------------------------------
scribble("================ new Object()");
obj = new Object(); // Object.create(null);
obj["property A"] = "value A";
obj["property B"] = "value B";
for (const p in obj) {
    // Note that hasOwnProperty() does not exist on the blank object created with Object.create(null).
    // When taking this approach (subclassed from some Object), it is recommended that you check
    // obj.hasOwnProperty( prop) to be sure you really are handling a property of the object you think you
    // are, rather than some inherited property you might not be expecting.  (Note that this probably won't)
    // work if you're trying to be polymorphic, in which case: why are you iterating properties like this?)
    if (obj.hasOwnProperty(p)) 
        scribble(p.toString() + ' = ' + obj[p]);
}

//-----------------------------------------------------------------------------------------------------------------
scribble("================ JSON");
class NavigationSectionInfo {
    constructor(public isDocumented: boolean, public subSections: Array<string>) { }

    get hasSubsections(): boolean { return this.subSections != null && this.subSections.length > 0; }
}

//-----------------------------------------------------------------------------------------------------------------
let dictMap = new Map<string, NavigationSectionInfo>();
dictMap.set("Section-1", new NavigationSectionInfo(true, null));
dictMap.set("Section-2", new NavigationSectionInfo(true, ["subsection-a", "subsection-b"]));

scribble("dictMap: " + JSON.stringify(dictMap));

//-----------------------------------------------------------------------------------------------------------------

// NOTE: This is the way to go for simple JSON objects
let dictObj = Object.create(null);
dictObj["Section-1"] = new NavigationSectionInfo(true, null);
dictObj["Section=2"] = new NavigationSectionInfo(true, ["subsection-a", "subsection-b"]);

scribble("dictObj: " + JSON.stringify(dictObj));

//-----------------------------------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------------------------------

/**
* Write the given message in a PRE element of the document.
*/
function scribble(aMsg: string): void {
    console.log(aMsg);
    // Get a reference to the document's PRE element, or null if there isn't one.
    var preElt = document.body.querySelector("pre");
    if (preElt) {
        // Do nothing, we're good
        // console.log("got preElt");
    }
    else {
        // console.log('make new pre elt');
        preElt = document.createElement("pre");
        // console.log('append pre elt to document body');
        document.body.appendChild(preElt);
    }
    // console.log('append new Text to pre elt');
    preElt.appendChild(new Text(aMsg + '\n'));
}