Easier-to-use variable height API

[dts]

This is a great library! Really smart architecture.

With mixed lists & complex UIs, it's not always the easiest thing to just spell out the heights of the items individually (mixing in group headers, etc). Fortunately, your basic structure doesn't require that! What works better for me, is to set an explicit style on each item that announces the height (i.e. <h1 style="height: 30px">Some Header</h1>), and then rewire the getVarSize thusly:

    // return a variable size (height) from given index.
    getVarSize: function (index, nocache) {
      var cache = this.delta.varCache[index]
      const get = (index) => {
        var item = this.$slots.default[index];
        if(item.data.staticStyle && item.data.staticStyle.height) {
          var m = item.data.staticStyle.height.match(/^(.*)px$/);
          return Number(m[1]);
        }
        
        return Number(item.data.attrs.height);
      }
      return (!nocache && cache && cache.size) || get(index) || 0
    },

If I were to push this as a PR, I'd make it so it does this if variable is set to true, and retain the original behavior if it's a function. Thoughts?

[tangbc]

Thank you, that's a good idea! Please make this pr.

I notice that in some vue version such as 2.0.0, item.data.attrs.height is not available:

data: {
    attrs: {
        style: 'height: 40px; line-height: 40px;'
    }
}

Please handle different versions of compatible processing, at least 2.0.0, and follow my code style 😀

[tangbc]

Well, let me finish it, you don't have to make pr.

[tangbc]

Released in v1.1.9

[dts]

cool! just so you know, there are two components to check: data.staticStyle and data.style - depending on how it's specified on the node.