# Developing Nodes

**URL:** https://discourse.nodered.org/c/developing-nodes/15.md?page=44

[Latest](https://discourse.nodered.org/latest.md) · [Categories](https://discourse.nodered.org/categories.md) · [Tags](https://discourse.nodered.org/tags.md)

**Page:** 45

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## [Examples that publish/subscribe MQTT?](https://discourse.nodered.org/t/examples-that-publish-subscribe-mqtt/7320)

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**Author:** [@ScottChapman](https://discourse.nodered.org/u/ScottChapman)\
**Replies:** 21\
**Last updated:** [2 October 2019 23:02 UTC](https://discourse.nodered.org/t/examples-that-publish-subscribe-mqtt/7320 "2019-10-02T23:02:03Z")

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I'm trying to create a couple of nodes that are basically publishing and subscribing to MQTT. I've got them configured so that I get the MQTT broker info. But I am not getting the 'connect' event. My code basically look…

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## [How to make custom UI widgets](https://discourse.nodered.org/t/how-to-make-custom-ui-widgets/15340)

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**Author:** [@limengsong](https://discourse.nodered.org/u/limengsong)\
**Replies:** 8\
**Last updated:** [30 September 2019 12:35 UTC](https://discourse.nodered.org/t/how-to-make-custom-ui-widgets/15340 "2019-09-30T12:35:28Z")

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How to make custom UI widgets in node-red. Just like TypedInput, EditableList, etc. Is there a tutorial for reference?

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## [Validators depending oneditprepare](https://discourse.nodered.org/t/validators-depending-oneditprepare/2398)

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**Author:** [@Sineos](https://discourse.nodered.org/u/Sineos)\
**Replies:** 2\
**Last updated:** [30 September 2019 05:43 UTC](https://discourse.nodered.org/t/validators-depending-oneditprepare/2398 "2019-09-30T05:43:54Z")

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With oneditprepare I switch the html form elements: oneditprepare: function() { $("#node-input-ThresholdType").change(function() { if ($(this).val() === "fixed") { $(".form-row-ThresholdTypeFixed").show(); …

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## [Host web application in custom node](https://discourse.nodered.org/t/host-web-application-in-custom-node/16060)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 10\
**Last updated:** [29 September 2019 23:40 UTC](https://discourse.nodered.org/t/host-web-application-in-custom-node/16060 "2019-09-29T23:40:55Z")

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Hi folks, We need to develop a new node that is able to host a web application. The (third-party) web application consists out of a number of files: Would like to build a custom node that allows users to start/stop …

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## [\[Announce\] uibuilder v2.0.4 published](https://discourse.nodered.org/t/announce-uibuilder-v2-0-4-published/16040)

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**Author:** [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Replies:** 0\
**Last updated:** [28 September 2019 22:43 UTC](https://discourse.nodered.org/t/announce-uibuilder-v2-0-4-published/16040 "2019-09-28T22:43:52Z")

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2.0.4 - 2019-09-28 Added uib icon (blue node-red icon) to the detailed information page (uibindex) & logo to README Look for the package.json browser property not just main and display it on the uibuindex page if a…

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## [Node-RED version string from within a custom node](https://discourse.nodered.org/t/node-red-version-string-from-within-a-custom-node/16033)

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**Author:** [@TotallyInformation](https://discourse.nodered.org/u/TotallyInformation)\
**Replies:** 2\
**Last updated:** [28 September 2019 21:04 UTC](https://discourse.nodered.org/t/node-red-version-string-from-within-a-custom-node/16033 "2019-09-28T21:04:20Z")

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Hi all, Does anyone know of a way to get hold of the Node-RED version string from within a custom node? e.g. something on the RED object or an API call? I want to pass it through to an API that uibuilder sets up that d…

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## [MQTT determine when the last "retained" message arrived](https://discourse.nodered.org/t/mqtt-determine-when-the-last-retained-message-arrived/15558)

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**Author:** [@Christian-Me](https://discourse.nodered.org/u/Christian-Me)\
**Replies:** 11\
**Last updated:** [26 September 2019 11:21 UTC](https://discourse.nodered.org/t/mqtt-determine-when-the-last-retained-message-arrived/15558 "2019-09-26T11:21:37Z")

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Hello I currently develop a cusom node for mqtt communication according to the homie convention. Devices using this "protocol" propagate there capabilities by a bunch of retained messages (in my setup over 450). It is …

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## [Custom Dashboard node without md-card - possible?](https://discourse.nodered.org/t/custom-dashboard-node-without-md-card-possible/14919)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 19\
**Last updated:** [24 September 2019 21:59 UTC](https://discourse.nodered.org/t/custom-dashboard-node-without-md-card-possible/14919 "2019-09-24T21:59:41Z")

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Hi folks, Steve ( @Steve-Mcl ) and I are developing node-red-contrib-ui-contextmenu. This ui node generates a simple “div” and “ul” element, which is filled and styled afterwards as soon, when a context menu needs to b…

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## [How to create Custom Node that has msg.payload value of all node properties combined ( in json format)](https://discourse.nodered.org/t/how-to-create-custom-node-that-has-msg-payload-value-of-all-node-properties-combined-in-json-format/15794)

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**Author:** [@jaya24](https://discourse.nodered.org/u/jaya24)\
**Replies:** 5\
**Last updated:** [23 September 2019 03:40 UTC](https://discourse.nodered.org/t/how-to-create-custom-node-that-has-msg-payload-value-of-all-node-properties-combined-in-json-format/15794 "2019-09-23T03:40:15Z")

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I am new to Node red. I need to create Custom Node that has msg.payload value of all node properties combined ( in json format) Thanks in advance.

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## [Watching directory with fs.watch not closing prev. watchers](https://discourse.nodered.org/t/watching-directory-with-fs-watch-not-closing-prev-watchers/6947)

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**Author:** [@Simo219h](https://discourse.nodered.org/u/Simo219h)\
**Replies:** 9\
**Last updated:** [22 September 2019 11:53 UTC](https://discourse.nodered.org/t/watching-directory-with-fs-watch-not-closing-prev-watchers/6947 "2019-09-22T11:53:33Z")

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Hi, I am struggling with a file that I am trying to watch for changes. I use the fs.watch, and listening on the 'change' event. It works fine, but when I hit the "Deploy" button in node-red, it opens another watcher, if…

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## [Temporary DOM elements somewhere cached](https://discourse.nodered.org/t/temporary-dom-elements-somewhere-cached/15520)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 4\
**Last updated:** [14 September 2019 07:00 UTC](https://discourse.nodered.org/t/temporary-dom-elements-somewhere-cached/15520 "2019-09-14T07:00:23Z")

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Hi folks, We have a nasty bug in our new SVG-node. Found at last where it is located and found a solution. But I don't understand the problem, don't know why the fix solves it and don't know if the fix will work on al…

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## [Clearing up a httpNode.post](https://discourse.nodered.org/t/clearing-up-a-httpnode-post/15463)

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**Author:** [@brettyj](https://discourse.nodered.org/u/brettyj)\
**Replies:** 3\
**Last updated:** [12 September 2019 20:38 UTC](https://discourse.nodered.org/t/clearing-up-a-httpnode-post/15463 "2019-09-12T20:38:50Z")

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Hey, I'm working on a node, which is listening on an endpoint which is set up using a RED.httpNode.post call. I'm having an issue where after deploy the node stops outputting messages, but I am getting a response on the…

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## [Msg payload printing the data](https://discourse.nodered.org/t/msg-payload-printing-the-data/15383)

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**Author:** [@Sanketp](https://discourse.nodered.org/u/Sanketp)\
**Replies:** 1\
**Last updated:** [11 September 2019 06:37 UTC](https://discourse.nodered.org/t/msg-payload-printing-the-data/15383 "2019-09-11T06:37:12Z")

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I want my custom node to print the message like file is created in the debug node how can i do this

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## [Simple debugging of Dashboard Widget](https://discourse.nodered.org/t/simple-debugging-of-dashboard-widget/7530)

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**Author:** [@Colin](https://discourse.nodered.org/u/Colin)\
**Replies:** 16\
**Last updated:** [10 September 2019 10:57 UTC](https://discourse.nodered.org/t/simple-debugging-of-dashboard-widget/7530 "2019-09-10T10:57:19Z")

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I am trying to do some simple debugging of the client side of a Dashboard Widget node-red-contrib-ui-led. I just want to be able to follow the flow to see if execution is getting where it should, so something like alert…

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## [Calling C/C++ functions from custom node](https://discourse.nodered.org/t/calling-c-c-functions-from-custom-node/13964)

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**Author:** [@Achronite](https://discourse.nodered.org/u/Achronite)\
**Replies:** 4\
**Last updated:** [9 September 2019 17:52 UTC](https://discourse.nodered.org/t/calling-c-c-functions-from-custom-node/13964 "2019-09-09T17:52:51Z")

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Hi All, I created a set of custom nodes for energenie devices a few months ago. The node uses functions written in C to interact with an energenie raspberry pi 433Mhz radio device. It currently uses the node ffi and re…

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## [Add image in Node help html file](https://discourse.nodered.org/t/add-image-in-node-help-html-file/15221)

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**Author:** [@Ekristoffe](https://discourse.nodered.org/u/Ekristoffe)\
**Replies:** 12\
**Last updated:** [8 September 2019 12:18 UTC](https://discourse.nodered.org/t/add-image-in-node-help-html-file/15221 "2019-09-08T12:18:58Z")

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Hello all, I am making a node and I am following the doc : https://nodered.org/docs/creating-nodes/ Or i can't find a way to add image in the html file for the help section (data-help-name) I want to be able to have t…

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## [Node-red custom node variable undefined](https://discourse.nodered.org/t/node-red-custom-node-variable-undefined/15205)

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**Author:** [@krishnaa208](https://discourse.nodered.org/u/krishnaa208)\
**Replies:** 5\
**Last updated:** [7 September 2019 08:15 UTC](https://discourse.nodered.org/t/node-red-custom-node-variable-undefined/15205 "2019-09-07T08:15:18Z")

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Hey I am trying to build a node for that taking input from user in dashboard and filter data based on input but \*\* i count not access array variable in .js ( undefined )\*\* file can someone help contents of .html are : …

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## [Hide/show tabsheet in config node dynamically](https://discourse.nodered.org/t/hide-show-tabsheet-in-config-node-dynamically/15177)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 8\
**Last updated:** [7 September 2019 06:33 UTC](https://discourse.nodered.org/t/hide-show-tabsheet-in-config-node-dynamically/15177 "2019-09-07T06:33:53Z")

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Hi folks, We have 3 tabsheets in the config screen of our node: this.tabs = RED.tabs.create({ id: "node-svg-tabs", }); this.tabs.addTab({ id: "node-svg-tab-source", label: "SVG source" }); this.tabs.add…

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## [Using local node for development & testing](https://discourse.nodered.org/t/using-local-node-for-development-testing/15179)

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**Author:** [@clickworkorange](https://discourse.nodered.org/u/clickworkorange)\
**Replies:** 3\
**Last updated:** [5 September 2019 22:09 UTC](https://discourse.nodered.org/t/using-local-node-for-development-testing/15179 "2019-09-05T22:09:56Z")

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I wanted to make a small change to the "Smooth" node, so I forked node-red-nodes on GitHub and checked out my fork to a local directory. I had installed NodeJS on my development machine (Devuan ASCII) with sudo apt-get i…

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## [Undefined class when using external js script](https://discourse.nodered.org/t/undefined-class-when-using-external-js-script/14993)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 5\
**Last updated:** [1 September 2019 21:45 UTC](https://discourse.nodered.org/t/undefined-class-when-using-external-js-script/14993 "2019-09-01T21:45:34Z")

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Hi folks, I'm trying (in my node's config screen) to instantiate a class that is supplied in a third party javascript file. Summarized it contains something like this: ... class EmbeddedSVGEdit { ... } ... export d…

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## [Pass over msg.payload to html](https://discourse.nodered.org/t/pass-over-msg-payload-to-html/14828)

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**Author:** [@matthiasertl](https://discourse.nodered.org/u/matthiasertl)\
**Replies:** 8\
**Last updated:** [27 August 2019 18:18 UTC](https://discourse.nodered.org/t/pass-over-msg-payload-to-html/14828 "2019-08-27T18:18:50Z")

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im trying topass over the answer from my modbus reader to a html page which i can read with my samsung smartthings device. the debug on the modbus reader shows my so called PV Power Value (e.g. \[1223\]) but i can not …

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## [Database connectivity inside a node](https://discourse.nodered.org/t/database-connectivity-inside-a-node/14731)

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**Author:** [@Sanketp](https://discourse.nodered.org/u/Sanketp)\
**Replies:** 3\
**Last updated:** [24 August 2019 06:58 UTC](https://discourse.nodered.org/t/database-connectivity-inside-a-node/14731 "2019-08-24T06:58:52Z")

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I created a node which has two fields name and password and i want to save this details inside the mongo but i dont want to use the in built mongodb connection node.

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## [How to debug an own node with the node.js debugger?](https://discourse.nodered.org/t/how-to-debug-an-own-node-with-the-node-js-debugger/5737)

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**Author:** [@noir](https://discourse.nodered.org/u/noir)\
**Replies:** 7\
**Last updated:** [22 August 2019 13:54 UTC](https://discourse.nodered.org/t/how-to-debug-an-own-node-with-the-node-js-debugger/5737 "2019-08-22T13:54:43Z")

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I'm creating an own node but I'm stuck with it so I want to find the error with the node.js debugger. However, setting breakpoints in any node seems not to work at all. Forgive me when this looks a bit hacky to you - I'…

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## [New node didn't show up on this site](https://discourse.nodered.org/t/new-node-didnt-show-up-on-this-site/1385)

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**Author:** [@blechdom](https://discourse.nodered.org/u/blechdom)\
**Replies:** 3\
**Last updated:** [18 August 2019 20:23 UTC](https://discourse.nodered.org/t/new-node-didnt-show-up-on-this-site/1385 "2019-08-18T20:23:50Z")

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I created my first node called node-red-contrib-dmxusbpro I can see it and download it manually from npm, but it doesn't show up on the flows page of this website. Can someone let me know if I did everything correctly? …

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## [Custom Node: collect & store runTime (mqtt) data in configuration note and access it from a node](https://discourse.nodered.org/t/custom-node-collect-store-runtime-mqtt-data-in-configuration-note-and-access-it-from-a-node/14176)

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**Author:** [@Christian-Me](https://discourse.nodered.org/u/Christian-Me)\
**Replies:** 12\
**Last updated:** [14 August 2019 04:49 UTC](https://discourse.nodered.org/t/custom-node-collect-store-runtime-mqtt-data-in-configuration-note-and-access-it-from-a-node/14176 "2019-08-14T04:49:20Z")

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Hello, I\*m new in developing my own nodes. My Idea is to develop a custom node to handle mqtt comunication according to the homie convention and use the auto discovery features for my sensor data. The initioal version s…

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## [Best way to update a TreeList in the node's config screen](https://discourse.nodered.org/t/best-way-to-update-a-treelist-in-the-nodes-config-screen/14046)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 2\
**Last updated:** [6 August 2019 13:06 UTC](https://discourse.nodered.org/t/best-way-to-update-a-treelist-in-the-nodes-config-screen/14046 "2019-08-06T13:06:54Z")

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Hi folks, Would like to use the TreeList widget in one of my nodes. As the documentation suggests, the current functionality is rather limited. For example there are no functions for dynamically adding/removing child…

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## [Pushcut Web API - Node for smart notifications?](https://discourse.nodered.org/t/pushcut-web-api-node-for-smart-notifications/13876)

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**Author:** [@sliemeobn](https://discourse.nodered.org/u/sliemeobn)\
**Replies:** 3\
**Last updated:** [31 July 2019 20:43 UTC](https://discourse.nodered.org/t/pushcut-web-api-node-for-smart-notifications/13876 "2019-07-31T20:43:00Z")

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I just released the brand new Web API for Pushcut, and my intention is to offer everything that is needed to integrate Pushcut with Node-RED in a good way. Here is the documentation. \<- You can even play around with the…

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## [UPDATE: node-red-contrib-mssql-plus V0.2.1](https://discourse.nodered.org/t/update-node-red-contrib-mssql-plus-v0-2-1/13654)

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**Author:** [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Replies:** 1\
**Last updated:** [24 July 2019 14:13 UTC](https://discourse.nodered.org/t/update-node-red-contrib-mssql-plus-v0-2-1/13654 "2019-07-24T14:13:43Z")

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Hi all, I now have access to the repo & NPM and have made some significant updates. All outstanding issues have (hopefully) been resolved... Fix problem where configs get mixed up when more than one SQL Server config …

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## [Toggle visibility of typedInput field - layout issue](https://discourse.nodered.org/t/toggle-visibility-of-typedinput-field-layout-issue/12756)

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**Author:** [@BartButenaers](https://discourse.nodered.org/u/BartButenaers)\
**Replies:** 12\
**Last updated:** [12 July 2019 12:46 UTC](https://discourse.nodered.org/t/toggle-visibility-of-typedinput-field-layout-issue/12756 "2019-07-12T12:46:43Z")

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Hi folks, In my camera-viewer node I have a dropdown, where you can choose between two options (push and pull). For each of those options, another typedinput field should be displayed. So when you select the 'push' op…

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## [typedInput and custom type validation](https://discourse.nodered.org/t/typedinput-and-custom-type-validation/13098)

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**Author:** [@Thierry](https://discourse.nodered.org/u/Thierry)\
**Replies:** 8\
**Last updated:** [10 July 2019 09:42 UTC](https://discourse.nodered.org/t/typedinput-and-custom-type-validation/13098 "2019-07-10T09:42:09Z")

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Hi, I have a typedInput field which uses a custom type. My custom type has a specific validate function which is working well inside the property panel (when the entered value does not match the validate pattern, then t…

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