define own filters

[emilos]

{"foo" | bar}

where bar would be a function that was passed as an option to the compiler.

await compile('{"foo" | bar}', { filters: { bar (value) { return value + "bar" } })

[pkonieczniak]

There is no problem when custom filter is named:

  let template = await compile('{foo | myFilter}', {
    filters: {
      myFilter: function myFilter (text) {
        return text.toUpperCase()
      } 
    }
  })

In case when someone defined function as anonymous or arrow fn then we cannot create AST.

In first example we received error Function declaration must have a name in this context

filters: {
 myFilter: function () {}
}

For this case we can return a new Function an append the name.

I think that more complex is handling arrow functions.

Babel has some plugins which can be used via node (transform-function-name, plugin-transform-arrow-functions)