用于传递枚举的Google闭包编译器注释

Question

I can't seem to find the correct closure-compiler annotations to pass a map of enums around.

Eg: Given EventTargets A , B with:

/** @enum {string} */
MYNS.A.EventType = {EA : 'ea1'};

/** @enum {string} */
MYNS.B.EventType = {EB : 'eb2'};

I have a constructor C that returns multiple EventTypes:

/** @return {WHATSTHIS} */
C.prototype.getEventTypesAB = function() {
  return {
    A: MYNS.A.EventType,
    B: MYNS.B.EventType
  };
};

to be used later:

goog.events.listen(parent, c.getEventTypesAB().A.EA, ...);

I've tried a few things such as below, which I guess doesn't work as enum is not a type , but am out of ideas of how to annotate this:

/** @typedef {{ A: MYNS.A.EventType, B: ... }} */

I always end up with the (expected) compiler warning: WARNING - Property EA never defined on String at the client.

Answer 1

MYNS.A.EventType is an object whose keys are strings and whose values are members of that enum. So you could write

/** @type {!Object<string, MYNS.A.EventType>} */ var obj = MYNS.A.EventType

and it would typecheck. Likewise for B. So the type of the object literal that you're returning is a record type, {A: !Object<string, MYNS.A.EventType>, B: !Object<string, MYNS.B.EventType>}

Answer 2

This code compiles with the online Closure Compiler Service :

goog.provide("MYNS.A.EventType");
goog.provide("MYNS.B.EventType");
goog.provide("MYNS.C.ComboType");
goog.provide("MYNS.C");
/** @enum {string} */
MYNS.A.EventType = {EA : 'ea1'};
/** @enum {string} */
MYNS.B.EventType = {EB : 'eb2'};
/** @typedef {{ A: MYNS.A.EventType, B: MYNS.B.EventType }} */
MYNS.C.ComboType;
MYNS.C = function() {};
/** @return {!MYNS.C.ComboType} */
C.prototype.getEventTypesAB = function() {
  return {
    A: MYNS.A.EventType,
    B: MYNS.B.EventType
  };
};
var foo = new C();
var r = foo.getEventTypesAB();
console.log(r.A.EA);
console.log(r.B.EB);

I haven't tried to run the resulting simple-compiled code, but it seems like it should work. Here is what the compiler gives with simple-compile and pretty print:

var MYNS = {A:{}, B:{}};
MYNS.A.EventType = {EA:"ea1"};
MYNS.B.EventType = {EB:"eb2"};
MYNS.C = function() {
};
C.prototype.getEventTypesAB = function() {
  return {A:MYNS.A.EventType, B:MYNS.B.EventType};
};
var foo = new C, r = foo.getEventTypesAB();
console.log(r.A.EA);
console.log(r.B.EB);

I think the step you are missing is to define the type with a namespace name as in these lines:

/** @typedef {{ A: MYNS.A.EventType, B: MYNS.B.EventType }} */
MYNS.C.ComboType;

That is what is shown on this page, which I consider the most helpful page about Google Closure syntax:

https://developers.google.com/closure/compiler/docs/js-for-compiler#tags