Adding new/experimental ECMA definitions

[rendaw]

Currently there's some ECMA objects that are new or experimental that aren't available in Elemental2: ClipboardItem, Intl.Segmenter, etc.

I tried to add my own shims like:

@JsType(isNative = true, name = "Intl.Segmenter", namespace = GLOBAL)
public class Segmenter {
  public Segmenter(String lang, JsPropertyMap<Object> options) {}

  public native JsArray<Segment> segment(String text);
}

but I get various errors

Segment$$Overlay.impl.java.js:13: ERROR - variable Segment is undeclared
  return instance instanceof Segment;
                             ^
  ProTip: "JSC_UNDEFINED_VARIABLE" or "checkVars" or "missingSourcesWarnings" or "undefinedVars" can be added to the `suppress` attribute of:

ERROR - Bad type annotation. Unknown type ClipboardItem
  ProTip: "JSC_UNRECOGNIZED_TYPE_ERROR" or "checkTypes" or "unrecognizedTypeError" can be added to the `suppress` attribute

ERROR - Property segment never defined on segmenter
  ProTip: "JSC_POSSIBLE_INEXISTENT_PROPERTY" or "checkTypes" or "globallyMissingProperties" or "missingProperties" or "missingSourcesWarnings" can be added to the `suppress` attribute

etc.

Since I have very minimal javascript I added the above to js_suppress, but is there a better/safer way to do this? I assume the reason elemental2 works while this doesn't is that elemental2 is checked against an internal js engine or something that doesn't have these defined (yet).

[tbroyer]

AFAICT, you need externs for all browser APIs. If these are not in Closure Library externs, then you have to write those and give them to the Closure Compiler.

[rendaw]

Thanks! That pointed me in the right direction.