How can you write duplicate virtual nodes in a component?

All virtual nodes(VNodes) in the component tree must be unique.i.e, You can't write duplicated nodes in a straightforward way. If you want to duplicate the same element/component many times then you should use factory function.

The below render function is invalid where you are trying to duplicate h1 element 3 times,

render: function (createElement) {
var myHeadingVNode = createElement('h1', 'This is a Virtual Node')
return createElement('div', [
myHeadingVNode, myHeadingVNode, myHeadingVNode
])
}

You can make duplicates with factory function,

render: function (createElement) {
return createElement('div',
Array.apply(null, { length: 3 }).map(function () {
return createElement('h1', 'This is a Virtual Node')
})
)
}