Handle unbound arguments from map and iterate calls on the JS client.

javascript/src/collection.js

@@ -21,11 +21,12 @@ goog.requireType('ee.Geometry');
  * @param {ee.Function} func The same argument as in ee.ComputedObject().
  * @param {Object} args The same argument as in ee.ComputedObject().
  * @param {string?=} opt_varName The same argument as in ee.ComputedObject().
+ * @param {boolean?=} opt_unbound The same argument as in ee.ComputedObject().
  * @constructor
  * @extends {ee.Element}
  */
-ee.Collection = function(func, args, opt_varName) {
-  ee.Collection.base(this, 'constructor', func, args, opt_varName);
+ee.Collection = function(func, args, opt_varName, opt_unbound) {
+  ee.Collection.base(this, 'constructor', func, args, opt_varName, opt_unbound);
   ee.Collection.initialize();
 };
 goog.inherits(ee.Collection, ee.Element);

javascript/src/computedobject.js

@@ -39,11 +39,13 @@ goog.requireType('ee.Function');
  *     and both 'func' and 'args' must be null. If all arguments are null, the
  *     object is considered an unnamed variable, and a name will be generated
  *     when it is included in an ee.CustomFunction.
+ * @param {?boolean=} opt_unbound Whether the object is unbound, i.e., called
+ *     from a mapped or iterated function.
  * @constructor
  * @extends {ee.Encodable}
  * @template T
  */
-ee.ComputedObject = function(func, args, opt_varName) {
+ee.ComputedObject = function(func, args, opt_varName, opt_unbound) {
   // Constructor safety.
   if (!(this instanceof ee.ComputedObject)) {
     return ee.ComputedObject.construct(ee.ComputedObject, arguments);
@@ -76,6 +78,12 @@ ee.ComputedObject = function(func, args, opt_varName) {
    * @protected
    */
   this.varName = opt_varName || null;
+
+  /**
+   * Whether the computed object is an unbound variable.
+   * @type {boolean}
+   */
+  this.unbound = !!opt_unbound;
 };
 goog.inherits(ee.ComputedObject, ee.Encodable);
 // Exporting manually to avoid marking the class public in the docs.
@@ -153,14 +161,20 @@ ee.ComputedObject.prototype.encodeCloudValue = function(serializer) {
   if (this.isVariable()) {
     const name = this.varName || serializer.unboundName;
     if (!name) {
-      // We are trying to call getInfo() or make some other server call inside a
-      // function passed to collection.map() or .iterate(), and the call uses
-      // one of the function arguments. The argument will be unbound outside of
-      // the map operation and cannot be evaluated. See the Count Functions case
-      // in customfunction.js for details on the unboundName mechanism.
-      // TODO(user): Report the name of the offending argument.
-      throw new Error(
-          'A mapped function\'s arguments cannot be used in client-side operations');
+      if (this.unbound) {
+        // We are trying to call getInfo() or make some other server call inside
+        // a function passed to collection.map() or .iterate(), and the call
+        // uses one of the function arguments. The argument will be unbound
+        // outside of the map operation and cannot be evaluated. See the Count
+        // Functions case in customfunction.js for details on the unboundName
+        // mechanism.
+        // TODO(user): Report the name of the offending argument.
+        throw new Error(`A mapped function's arguments (${
+            this.name()}) cannot be used in client-side operations.`);
+      } else {
+        throw new Error(
+            `Invalid cast to ${this.name()} from a client-side object.`);
+      }
     }
     return ee.rpc_node.argumentReference(name);
   } else {

javascript/src/customfunction.js

@@ -138,6 +138,7 @@ ee.CustomFunction.variable = function(type, name) {
     this.func = null;
     this.args = null;
     this.varName = name;
+    this.unbound = true;
   };
   klass.prototype = type.prototype;
   return new klass(name);

javascript/src/dictionary.js

@@ -46,16 +46,19 @@ ee.Dictionary = function(opt_dict) {
   if (ee.Types.isRegularObject(opt_dict)) {
     // Cast to a dictionary.
     ee.Dictionary.base(this, 'constructor', null, null);
-    this.dict_ = /** @type {Object} */ (opt_dict);
+    this.dict_ = /** @type {!Object} */ (opt_dict);
   } else {
     if (opt_dict instanceof ee.ComputedObject && opt_dict.func &&
         opt_dict.func.getSignature()['returns'] == 'Dictionary') {
       // If it's a call that's already returning a Dictionary, just cast.
-      ee.Dictionary.base(this, 'constructor', opt_dict.func, opt_dict.args, opt_dict.varName);
+      ee.Dictionary.base(this, 'constructor', opt_dict.func, opt_dict.args, opt_dict.varName, opt_dict.unbound);
     } else {
+      const unbound =
+          opt_dict instanceof ee.ComputedObject ? opt_dict.unbound : null;
       // Delegate everything else to the server-side constructor.
       ee.Dictionary.base(
-          this, 'constructor', new ee.ApiFunction('Dictionary'), {'input': opt_dict}, null);
+          this, 'constructor', new ee.ApiFunction('Dictionary'),
+          {'input': opt_dict}, null, unbound);
     }
     this.dict_ = null;
   }

javascript/src/element.js

@@ -19,11 +19,12 @@ goog.requireType('ee.Function');
  * @param {ee.Function} func The same argument as in ee.ComputedObject().
  * @param {Object} args The same argument as in ee.ComputedObject().
  * @param {string?=} opt_varName The same argument as in ee.ComputedObject().
+ * @param {boolean?=} opt_unbound The same argument as in ee.ComputedObject().
  * @constructor
  * @extends {ee.ComputedObject}
  */
-ee.Element = function(func, args, opt_varName) {
-  ee.Element.base(this, 'constructor', func, args, opt_varName);
+ee.Element = function(func, args, opt_varName, opt_unbound) {
+  ee.Element.base(this, 'constructor', func, args, opt_varName, opt_unbound);
   ee.Element.initialize();
 };
 goog.inherits(ee.Element, ee.ComputedObject);

javascript/src/feature.js

@@ -57,7 +57,7 @@ ee.Feature = function(geometry, opt_properties) {
     });
   } else if (geometry instanceof ee.ComputedObject) {
     // A custom object to reinterpret as a Feature.
-    ee.Feature.base(this, 'constructor', geometry.func, geometry.args, geometry.varName);
+    ee.Feature.base(this, 'constructor', geometry.func, geometry.args, geometry.varName, geometry.unbound);
   } else if (geometry['type'] == 'Feature') {
     // Try to convert a GeoJSON Feature.
     var properties = geometry['properties'] || {};

javascript/src/filter.js

@@ -65,7 +65,7 @@ ee.Filter = function(opt_filter) {
     }
   } else if (opt_filter instanceof ee.ComputedObject) {
     // Actual filter object.
-    ee.Filter.base(this, 'constructor', opt_filter.func, opt_filter.args, opt_filter.varName);
+    ee.Filter.base(this, 'constructor', opt_filter.func, opt_filter.args, opt_filter.varName, opt_filter.unbound);
     this.filter_ = [opt_filter];
   } else if (opt_filter === undefined) {
     // A silly call with no arguments left for backward-compatibility.

javascript/src/geometry.js

@@ -87,7 +87,7 @@ ee.Geometry = function(geoJson, opt_proj, opt_geodesic, opt_evenOdd) {
           'Setting the CRS, geodesic, or evenOdd flag on a computed Geometry ' +
           'is not supported.  Use Geometry.transform().');
     } else {
-      ee.Geometry.base(this, 'constructor', geoJson.func, geoJson.args, geoJson.varName);
+      ee.Geometry.base(this, 'constructor', geoJson.func, geoJson.args, geoJson.varName, geoJson.unbound);
       return;
     }
   }

javascript/src/image.js

@@ -77,7 +77,7 @@ ee.Image = function(opt_args) {
                   {'value': opt_args});
       } else {
         // A custom object to reinterpret as an Image.
-        ee.Image.base(this, 'constructor', opt_args.func, opt_args.args, opt_args.varName);
+        ee.Image.base(this, 'constructor', opt_args.func, opt_args.args, opt_args.varName, opt_args.unbound);
       }
     } else {
       throw Error('Unrecognized argument type to convert to an Image: ' +

javascript/src/imagecollection.js

@@ -70,7 +70,7 @@ ee.ImageCollection = function(args) {
     });
   } else if (args instanceof ee.ComputedObject) {
     // A custom object to reinterpret as an ImageCollection.
-    ee.ImageCollection.base(this, 'constructor', args.func, args.args, args.varName);
+    ee.ImageCollection.base(this, 'constructor', args.func, args.args, args.varName, args.unbound);
   } else {
     throw Error('Unrecognized argument type to convert to an ' +
                 'ImageCollection: ' + args);

javascript/src/list.js

@@ -45,7 +45,7 @@ ee.List = function(list) {
     ee.List.base(this, 'constructor', null, null);
     this.list_ = /** @type {IArrayLike} */ (list);
   } else if (list instanceof ee.ComputedObject) {
-    ee.List.base(this, 'constructor', list.func, list.args, list.varName);
+    ee.List.base(this, 'constructor', list.func, list.args, list.varName, list.unbound);
     this.list_ = null;
   } else {
     throw Error('Invalid argument specified for ee.List(): ' + list);

javascript/src/number.js

@@ -43,7 +43,7 @@ ee.Number = function(number) {
     ee.Number.base(this, 'constructor', null, null);
     this.number_ = /** @type {number} */ (number);
   } else if (number instanceof ee.ComputedObject) {
-    ee.Number.base(this, 'constructor', number.func, number.args, number.varName);
+    ee.Number.base(this, 'constructor', number.func, number.args, number.varName, number.unbound);
     this.number_ = null;
   } else {
     throw Error('Invalid argument specified for ee.Number(): ' + number);

javascript/src/string.js

@@ -46,9 +46,9 @@ ee.String = function(string) {
     this.string_ = null;
     if (string.func && string.func.getSignature()['returns'] == 'String') {
       // If it's a call that's already returning a String, just cast.
-      ee.String.base(this, 'constructor', string.func, string.args, string.varName);
+      ee.String.base(this, 'constructor', string.func, string.args, string.varName, string.unbound);
     } else {
-      ee.String.base(this, 'constructor', new ee.ApiFunction('String'), {'input': string}, null);
+      ee.String.base(this, 'constructor', new ee.ApiFunction('String'), {'input': string}, null, string.unbound);
     }
   } else {
     throw Error('Invalid argument specified for ee.String(): ' + string);