closes #1851

lib/browser/tag/tag.js

@@ -213,6 +213,8 @@ export default function Tag(impl, conf, innerHTML) {
     updateOpts.call(this)
     if (impl.fn) impl.fn.call(this, opts)
 
+    this.trigger('before-mount')
+
     // update the root adding custom attributes coming from the compiler
     implAttrs = []
     walkAttrs(impl.attrs, (k, v) => { implAttrs.push({name: k, value: v}) })

test/specs/browser/core.spec.js

@@ -562,6 +562,25 @@ describe('Riot core', function() {
     expect(incrementEvents).to.have.been.calledTwice
   })
 
+  it('the before mount event gets triggered before the component markup creation', function() {
+    injectHTML('<riot-tmp></riot-tmp>')
+
+    riot.tag('riot-tmp', `
+      <p>{ flag }<p>
+    `, function() {
+      this.flag = true
+      this.on('before-mount', () => {
+        this.flag = false
+      })
+    })
+
+    var tag = riot.mount('riot-tmp')[0]
+
+    expect($('p', tag.root).innerHTML).to.be.equal('false')
+
+    tag.unmount()
+  })
+
   it('all the events get fired also in the loop tags, the e.item property gets preserved', function() {
     injectHTML('<events></events>')
     var currentItem,