event-header.js

(function() {
  function stringifyEvent(event) {
    var obj = {}
    for (var key in event) {
      obj[key] = event[key]
    }
    return JSON.stringify(obj, function(key, value) {
      if (value instanceof Node) {
        var nodeRep = value.tagName
        if (nodeRep) {
          nodeRep = nodeRep.toLowerCase()
          if (value.id) {
            nodeRep += '#' + value.id
          }
          if (value.classList && value.classList.length) {
            nodeRep += '.' + value.classList.toString().replace(' ', '.')
          }
          return nodeRep
        } else {
          return 'Node'
        }
      }
      if (value instanceof Window) return 'Window'
      return value
    })
  }

  htmx.defineExtension('event-header', {
    onEvent: function(name, evt) {
      if (name === 'htmx:configRequest') {
        if (evt.detail.triggeringEvent) {
          evt.detail.headers['Triggering-Event'] = stringifyEvent(evt.detail.triggeringEvent)
        }
      }
    }
  })
})()