How to best process an [object Promise]?

[ninjabreadman]

@E3V3A I don’t think there’s a reload mechanism in MM’s config.js. For example, you can have an updateInterval variable in the module config, but it’s the module’s job to then implement the refresh – it isn’t done automagically by MM.

See the code for the default compliments module for where it uses this.config.updateInterval to call setInterval() with updateDom() (to set a timer to reload the DOM after a delay) all within its start() function.

[Mykle1]

@ninjabreadman said in How to best process an [object Promise]?:

automagically

Absolutely the best term I have heard to date. :-)

[E3V3A]

@Mykle1 said in How to best process an [object Promise]?:

@ninjabreadman said in How to best process an [object Promise]?:

automagically

Absolutely the best term I have heard to date. :-)

:) Especially in this context! I’m only now starting to understand why it’s called a magic mirror… Whatever you guys manage to create, it seem to have been done by development magic…

But, anyway, my problem is surely just a lack of conceptual and technical knowledge.

In my node_helper.js I was tryign to do this:

const NodeHelper = require("node_helper");
const fs = require('fs');
const async = require('async');
const radar = require('radar-api'); // This API return improper JSON

module.exports = NodeHelper.create({
...
    async function radarPing() {
        console.log("ENTER (inside)");
        try {
            const ping = await radar(-8.20917,114.62177,-9.28715,115.71243);
            console.log("GOT DATA: ", await ping);
            return await ping;
        } catch(error) {
            console.log("API ERROR: ", error);
        }
        //return "None";
        console.log("EXIT (inside)");
    },

    readData: function() {
        var radarData = "";
        radarData = radarPing();
        console.log("The DATA:\n" + radarData);
...

but that ended up with some weird errors, like:

            const ping = await radar(-8.20917,114.62177,-9.28715,115.71243); 
                               ^^^^^
SyntaxError: Unexpected identifier
    at Object.exports.runInThisContext (vm.js:76:16)
    at Module._compile (module.js:528:28)

Since, I’ve only started to learn about Promises, sync/await, just 2 days ago, I must be missing a lot. Because all the examples I’ve seen, are using more or less this way of writing.

So how the eeek do I make sure that what is returned by the api/poll function, is actual data and not an [object Promise], and how can I handle the Promise { } that is returned in advance?

I’m overwhelmed…

[E3V3A]

I also tried another variant, but that failed too:

    radarPing: function() {
        console.log("ENTER (inside)");
        try {
            var ping = radar(-8.20917,114.62177,-9.28715,115.71243); 
            ping.then({
            return ping;
            //...
            });
            console.log("GOT DATA: ", ping);
            //return await ping;
        } catch(error) {
            console.log("API ERROR: ", error);
        }
        //return "None";
        console.log("EXIT (inside)");
    },

    readData: function() {
        var radarData = "";
        radarData = this.radarPing;
        console.log("The DATA:\n" + radarData);
...

[E3V3A]

I’ve got a partially working function, but it’s a bit funny. For some reason the call to cleanup the JSON is not liked, because it seem that the actual result is not returned, but the Promise .

This is the code snippet:

radarPing: function() {
    console.log("ENTER (inside)");
    Promise.all([
        radar(-8.20917,114.62177,-9.28715,115.71243)
        ]).then(function(results) {
            var ping = results;
            console.log("PING1:");
            console.log(ping);
            var cleanData = jZen(ping);
            console.log("PING2: ", cleanData);
            self.sendSocketNotification("NEW_DATA", ping); //"PING"
            return cleanData; //ping;
        });
    console.log("EXIT (inside)");
},

    readData: function() {
        //const myfile = 'modules/MMM-FlightsAbove/demo.json'; // The demo API use improper JSON
        var radarData = "";
        radarData = this.radarPing();
        console.log("The DATA:\n", radarData);

/*        if ( radarData === "" ) {
        }
*/        //let cleanData = jZen(data);
        //let cleanData = jZen(radarData);
        let cleanData = radarData;
        if (isJSON(cleanData) ) {
            this.sendSocketNotification("NEW_DATA", cleanData);
        } else {
            // So WTF is it?
            console.log("- JSON: false");
            console.log("- isAO(dirty): " + isAO(radarData));
            console.log("- isAO(clean): " + isAO(cleanData));
            console.log("- Data:\n", radarData);
        }
    },
...
});

// To check if something is JSON
function isJSON(str) {
    try { return (JSON.parse(str) && !!str); }
    catch (e) { return false; }
}

// To check if something is an Array or Object (parsed JSON)
function isAO(val) {
    return val instanceof Array || val instanceof Object ? true : false;
}

// --------------------------------------------------------------------------
// What:  A dirt simple JSON cleanup function that also compactifies the data
// NOTE:  - Only use on flat and trustworthy ASCII JSON data!
//        - Cannot handle any characters outside [A-Za-z0-9_\-]. (e.g. UTF-8)
//        - Using remote data without further sanitation is a security risk!
// --------------------------------------------------------------------------
const re1 = /([A-Za-z0-9_\-]+):/gm;  // use const to make sure it is compiled
function jZen(juice) {
    //let re1 = /([A-Za-z0-9_\-]+):/gm; // Find all ASCII words $1 before an ":"
    //let data = juice;
    let str = "";
    str = juice.replace(/\s/gm, '');     // Remove all white-space
    str = str.replace(/\'/gm, '\"');    // Replace all ' with "
    str = str.replace(re1, '\"$1\":');  // Replace $1: with "$1":
    //console.log("Dirty JSON is:\n" + data.toString() );
    //console.log("Clean JSON is:\n" + str);
    return str;
}

The output is:

...
ENTER (inside)
EXIT (inside)
The DATA:
 undefined
- JSON: false
- isAO(dirty): false
- isAO(clean): false
- Data:
 undefined
PING1:
[ [ { id: '108be389',
      timestamp: 1519647028,
      registration: 'PK-GQL',
      flight: 'QG8816',
      callsign: 'CTV8816',
...

As you can see, PING2 never happens…