mysql get data and send it to gui dropdown box

[esc...@missionroom.nl]

I am trying to send data from the database to a gui dropdown box.

The proble is that i get an array with arrays and for the dropdown i need an array with object

I use this code to send to the sql node

msg.topic = "SELECT title, id FROM services";

return msg;

runs wel and this gives me

[ { "title": "Thema A", "id": 1 }, { "title": "Thema B", "id": 2 }, { "title": "Thema C", "id": 3 } ]

but what i need is 

[ { "Thema A", 1 }, { "Thema B", 2 }, { "Thema C", 3 } ]

i tried to do this with the code below

var outputArray = [];

for(var i in msg.payload){

    var entryData = [msg.payload[i]['title']];

    for(var attr in msg.payload[i]) {

        if(attr!='title') {

            entryData.push(msg.payload[i][attr])}

            }

    outputArray.push(entryData); } 

var returnMsg={"options":outputArray};

return returnMsg;

That gives me

[ [ "Thema A", 1 ], [ "Thema B", 2 ], [ "Thema C", 3 ] ]

But.... the arrays should be objects to be working with the gui dropdownbox

All tips are welcome!

Thanks!

[Nick O'Leary]

Hi,

The 'map' function is very useful when you have an array of data that you need to transform like this.

msg.options = msg.payload.map(function(el) {

    var result = {};

    result[el.title] = el.id;

    return result;

});

return msg;

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Array/map

Nick

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[esc...@missionroom.nl]

Amazing!

Thanks for your speedy and working reply!!

Op woensdag 8 februari 2017 21:05:48 UTC+1 schreef Nick O'Leary:

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[steve rickus]

This same request seems to crop up frequently, so I was thinking that a node to do this would be handy.

Then I remembered that there is some JSONata syntax that does this very simply:  $.{title: id}

Nick, I remember you said we could use that syntax in a few places, but there is no JSONata node, is there? So how can we invoke that "magic" transformation using the core nodes?

--

Steve

[Nick O'Leary]

As per the release blog post, the change node has jsonata support - it's in the dropdown list of types.

Nick

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[steve rickus]

Ah, brilliant! The change node works nicely, once I modified the expression to be  msg.payload.{title: id}

FWIW, it would help a bit to have an example (maybe this one!) in the sidebar info.

[

    {

        "id": "f7b73b78.3823b8",

        "type": "inject",

        "z": "a896d148.586bc",

        "name": "Array of objects",

        "topic": "",

        "payload": "[ { \"title\": \"Thema A\", \"id\": 1 }, { \"title\": \"Thema B\", \"id\": 2 }, { \"title\": \"Thema C\", \"id\": 3 } ]",

        "payloadType": "json",

        "repeat": "",

        "crontab": "",

        "once": false,

        "x": 140,

        "y": 340,

        "wires": [

            [

                "6fa91881.dc6378"

            ]

        ]

    },

    {

        "id": "6fa91881.dc6378",

        "type": "change",

        "z": "a896d148.586bc",

        "name": "build {key: val} array",

        "rules": [

            {

                "t": "set",

                "p": "payload",

                "pt": "msg",

                "to": "msg.payload.{title: id}",

                "tot": "jsonata"

            }

        ],

        "action": "",

        "property": "",

        "from": "",

        "to": "",

        "reg": false,

        "x": 380,

        "y": 340,

        "wires": [

            [

                "306cc493.091e5c"

            ]

        ]

    },

    {

        "id": "306cc493.091e5c",

        "type": "debug",

        "z": "a896d148.586bc",

        "name": "",

        "active": true,

        "console": "false",

        "complete": "false",

        "x": 630,

        "y": 340,

        "wires": []

    }

]

Of course, it's probably a toss-up as to whether JSONata syntax or the map(...)  function is more confusing to the uninitiated...

Live and learn!