UI dropdown: select falsy value

[bartbutenaers]

Description

When a falsy value (i.e. false, "", or 0) has been selected, the output message will contain payload null.

Example flow:

[{"id":"f192ce1f9de95a8c","type":"ui-dropdown","z":"a663bb334b6ef130","group":"8b1a9ffb134b44f3","name":"","label":"Select Option:","tooltip":"","order":0,"width":0,"height":0,"passthru":false,"multiple":false,"chips":false,"clearable":false,"options":[{"label":"Empty string","value":"","type":"str"},{"label":"False","value":false,"type":"bool"},{"label":"0","value":0,"type":"num"}],"payload":"","topic":"topic","topicType":"msg","className":"","typeIsComboBox":false,"msgTrigger":"onChange","x":1360,"y":100,"wires":[["a68f0818785ba8ef"]]},{"id":"a68f0818785ba8ef","type":"debug","z":"a663bb334b6ef130","name":"debug 2","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":1540,"y":100,"wires":[]},{"id":"8b1a9ffb134b44f3","type":"ui-group","name":"Group Name","page":"71988bc054a986f5","width":6,"height":1,"order":-1,"showTitle":true,"className":"","visible":"true","disabled":"false","groupType":"default"},{"id":"71988bc054a986f5","type":"ui-page","name":"Page 2","ui":"ba0979b23b606ba0","path":"/page2","icon":"home","layout":"grid","theme":"c049776195a75b90","breakpoints":[{"name":"Default","px":"0","cols":"3"},{"name":"Tablet","px":"576","cols":"6"},{"name":"Small Desktop","px":"768","cols":"9"},{"name":"Desktop","px":"1024","cols":"12"}],"order":-1,"className":"","visible":"true","disabled":"false"},{"id":"ba0979b23b606ba0","type":"ui-base","name":"My Dashboard","path":"/dashboard","appIcon":"","includeClientData":true,"acceptsClientConfig":["ui-notification","ui-control"],"showPathInSidebar":false,"navigationStyle":"default","titleBarStyle":"default","showReconnectNotification":true,"notificationDisplayTime":1,"showDisconnectNotification":true},{"id":"c049776195a75b90","type":"ui-theme","name":"Default Theme","colors":{"surface":"#ffffff","primary":"#0094CE","bgPage":"#eeeeee","groupBg":"#ffffff","groupOutline":"#cccccc"},"sizes":{"density":"default","pagePadding":"12px","groupGap":"12px","groupBorderRadius":"4px","widgetGap":"12px"}}]

Related Issue(s)

1585

Checklist

• I have read the contribution guidelines
• Suitable unit/system level tests have been added and they pass
• Documentation has been updated
  • Upgrade instructions
  • Configuration details
  • Concepts
• Changes flowforge.yml?
  • Issue/PR raised on FlowFuse/helm to update ConfigMap Template
  • Issue/PR raised on FlowFuse/CloudProject to update values for Staging/Production

Labels

• Includes a DB migration? -> add the area:migration label