local-server.js

var express = require('express');
var app = express();
var fs = require("fs");
var { mapValues } = require("lodash");

var bp = require("body-parser");
var cors = require("cors");

app.use(bp.json());
app.use(cors());

var timer = null;
var cmTimer = null;
var timeout = 250;

var db = {d: { results: JSON.parse(fs.readFileSync(__dirname + "/db.json", { charset: "utf8" })) } };
var db_ = db.d.results.reduce(function ( obj, item ) {
    obj[item.ID] = { d: item };
    return obj;
}, {});

// GET LIST
app.get("/items", function ( req, res ) {
    if ( timer ) {
        clearTimeout(timer);
    }
    timer = setTimeout(function () {
        res.send(db);
    }, timeout);
});

// DO THE CONTEXT THINGY
app.post("/Pages/content/_api/contextinfo", function ( req, res ) {
    if ( timer ) {
        clearTimeout(timer);
    }
    timer = setTimeout(function () {
        res.send({
            d: {
                GetContextWebInformation: {
                    FormDigestValue: "1234"
                }
            }
        });
    }, timeout);
});

// OPTIONS
app.get("/opt", function ( req, res ) {
    if ( cmTimer ) {
        clearTimeout(cmTimer);
    }
    cmTimer = setTimeout(function () {
        res.send({
            d: {
                results: [
                    {
                        Variable: "hideSearchWhileEditing",
                        Value: true
                    }, {
                        Variable: "images",
                        Value: "https://jsbin-user-assets.s3.amazonaws.com/dhenson02"
                    }, {
                        Variable: "scrollOnNav",
                        Value: false
                    }, {
                        Variable: "resetOpenOnNav",
                        Value: false
                    }
                ]
            }
        });
    }, timeout);
});

// GET ITEM
app.get("/items(:id)", function ( req, res ) {
    var id = req.params.id.slice(1,-1);
    if ( timer ) {
        clearTimeout(timer);
    }
    timer = setTimeout(function () {
        res.send(db_[id]);
    }, timeout);
});

// SAVE ITEM
app.post("/items(:id)", function ( req, res ) {
    var id = req.params.id.slice(1, -1);
    var data = mapValues(req.body, function ( val, key ) {
        if ( key === "__metadata" ) {
            return db_[id].d.__metadata;
        }
        return ( Array.isArray(val) ) ? { results: val } : val;
    });
    data.ID = id;
    data.Id = id;
    db_[id].d = Object.assign({}, db_[id].d, data);
    db.d.results = db.d.results.map(function ( item ) {
        if ( item.ID === id ) {
            item = db_[id].d;
        }
        return item;
    });
    fs.writeFileSync(__dirname + "/db.json", JSON.stringify(db.d.results), { charset: "utf8" });

    if ( timer ) {
        clearTimeout(timer);
    }
    timer = setTimeout(function () {
        res.send({ status: "success" });
    }, timeout);
});

// CREATE ITEM
app.post('/items', function ( req, res ) {
    var id = Number(Object.keys(db_).sort(function ( x, y ) { return x - y; }).pop()) + 1;
    var data = mapValues(req.body, function ( val ) {
        return ( Array.isArray(val) ) ? { results: val } : val;
    });
    data.ID = id;
    data.Id = id;
    db.d.results.push(data);
    db_[id] = { d: data };
    fs.writeFileSync(__dirname + "/db.json", JSON.stringify(db.d.results), { charset: "utf8" });
    if ( timer ) {
        clearTimeout(timer);
    }
    timer = setTimeout(function () {
        res.send({ status: "success" });
    }, timeout);
});

// IS CONTENT MANAGER?
app.get("/check/true", function ( req, res ) {
    if ( cmTimer ) {
        clearTimeout(cmTimer);
    }
    cmTimer = setTimeout(function () {
        res.send({ status: "success" });
    }, timeout);
});

var server = app.listen(3001, function () {
    var host = server.address().address;
    var port = server.address().port;

    console.log('Local development server listening at http://%s:%s', host, port);
});