SOURCE

// PREFER
var BetterHeader = {
    view: function(vnode) {
        return m(".section", [
            m(".header", vnode.attrs.title),
            m(".tagline", vnode.attrs.tagline),
        ])
    }
}

m(BetterHeader, {
    title: m("h1", "My title"),
    tagline: m("h2", "Lorem ipsum"),
})

// clearer consumption use case
m(BetterHeader, {
    title: [
        m("h1", "My title"),
        m("small", "A small note"),
    ],
    tagline: m("h2", "Lorem ipsum"),
})

<div id="demo1"></div>
<div id="demo2"></div>
<div id="demo3"></div>
<div id="demo4"></div>