The as Expression


  <expression> as [ a | an ] CONVERSION


Hyperscript provides a pluggable conversion system with the as expression. It will look up the conversion of the given name and apply it to the input expression.

By default, hyperscript provides the following conversions:

Some examples:

  log '10' as Int            -- logs 10
  log '3.141568' as Fixed:2  -- logs '3.14'
  log '{"foo":10}' as Object -- logs { "foo": 10 }'
  log 10 as String           -- logs "10"

You can add new conversions by adding them to the _hyperscript.config.conversions object:

_hyperscript.config.conversions["MyConversion"] = function (val) {
  return "I converted: " + val;

which can then be used like so in hyperscript:

<button _="on click put 'foo' as MyConversion into my innerHTML">
  Call my conversion

You also have the option to create a dynamic conversion, which will be called before all conversions, and allow you to create more flexible conversion naming schemes

_hyperscript.config.conversions.dynamicResolvers.push(function (
) {
  if (conversionName.indexOf("MyConversion:") == 0) {
    var arg = conversionName.split(":")[1];
    if (arg === "Short") {
      return "I converted : " + val;
    } else if (arg === "Long") {
      return "I am happy to announce I converted : " + val;

This conversion could now be used like so:

<button _="on click put 'foo' as MyConversion:Short into my innerHTML">
  Call my conversion