Move patchBase into options in Zotero.Item.prototype.toJSON()

Also:

- Make .mode == 'patch' optional if .patchBase is provided.
- Remove requirement for item to be unchanged, which hopefully wasn't there for
  a good reason
- Add a few tests, though more are needed

chrome/content/zotero/xpcom/data/item.js

@@ -4138,12 +4138,9 @@ Zotero.Item.prototype.fromJSON = Zotero.Promise.coroutine(function* (json) {
 
 /**
  * @param {Object} options
- * @param {Object} patchBase
  */
-Zotero.Item.prototype.toJSON = Zotero.Promise.coroutine(function* (options, patchBase) {
+Zotero.Item.prototype.toJSON = Zotero.Promise.coroutine(function* (options) {
-	if (this.hasChanged()) {
+	options = options || {};
-		throw new Error("Cannot generate JSON from changed item");
-	}
 	
 	if (options) {
 		var mode = options.mode;
@@ -4153,13 +4150,19 @@ Zotero.Item.prototype.toJSON = Zotero.Promise.coroutine(function* (options, patc
 	}
 	
 	if (mode == 'patch') {
-		if (!patchBase) {
+		if (!options.patchBase) {
 			throw new Error("Cannot use patch mode if patchBase not provided");
 		}
 	}
-	else if (patchBase) {
+	else if (options.patchBase) {
+		if (options.mode) {
 			Zotero.debug("Zotero.Item.toJSON: ignoring provided patchBase in " + mode + " mode", 2);
 		}
+		// If patchBase provided and no explicit mode, use 'patch'
+		else {
+			mode = 'patch';
+		}
+	}
 	
 	var obj = {};
 	obj.key = this.key;
@@ -4254,7 +4257,7 @@ Zotero.Item.prototype.toJSON = Zotero.Promise.coroutine(function* (options, patc
 	obj.dateModified = Zotero.Date.sqlToISO8601(this.dateModified);
 	
 	if (mode == 'patch') {
-		for (let i in patchBase) {
+		for (let i in options.patchBase) {
 			switch (i) {
 			case 'key':
 			case 'version':
@@ -4263,7 +4266,7 @@ Zotero.Item.prototype.toJSON = Zotero.Promise.coroutine(function* (options, patc
 			}
 			
 			if (i in obj) {
-				if (obj[i] === patchBase[i]) {
+				if (obj[i] === options.patchBase[i]) {
 					delete obj[i];
 				}
 			}
@@ -4277,12 +4280,12 @@ Zotero.Item.prototype.toJSON = Zotero.Promise.coroutine(function* (options, patc
 });
 
 
-Zotero.Item.prototype.toResponseJSON = Zotero.Promise.coroutine(function* (options, patchBase) {
+Zotero.Item.prototype.toResponseJSON = Zotero.Promise.coroutine(function* (options) {
 	var json = {
 		key: this.key,
 		version: this.version,
 		meta: {},
-		data: yield this.toJSON(options, patchBase)
+		data: yield this.toJSON(options)
 	};
 	
 	// TODO: library block?

test/tests/itemTest.js

@@ -420,4 +420,58 @@ describe("Zotero.Item", function () {
 			assert.sameDeepMembers(item.getTags(tags), tags.slice(0));
 		})
 	})
+	
+	describe("#toJSON()", function () {
+		it("should output only fields with values in default mode", function* () {
+			var itemType = "book";
+			var title = "Test";
+			
+			var item = new Zotero.Item(itemType);
+			item.setField("title", title);
+			var id = yield item.save();
+			item = yield Zotero.Items.getAsync(id);
+			var json = yield item.toJSON();
+			
+			assert.equal(json.itemType, itemType);
+			assert.equal(json.title, title);
+			assert.isUndefined(json.date);
+			assert.isUndefined(json.numPages);
+		})
+		
+		it("should output all fields in 'full' mode", function* () {
+			var itemType = "book";
+			var title = "Test";
+			
+			var item = new Zotero.Item(itemType);
+			item.setField("title", title);
+			var id = yield item.save();
+			item = yield Zotero.Items.getAsync(id);
+			var json = yield item.toJSON({ mode: 'full' });
+			assert.equal(json.title, title);
+			assert.equal(json.date, "");
+			assert.equal(json.numPages, "");
+		})
+		
+		it("should output only fields that differ in 'patch' mode", function* () {
+			var itemType = "book";
+			var title = "Test";
+			var date = "2015-05-12";
+			
+			var item = new Zotero.Item(itemType);
+			item.setField("title", title);
+			var id = yield item.save();
+			item = yield Zotero.Items.getAsync(id);
+			var patchBase = yield item.toJSON();
+			
+			item.setField("date", date);
+			yield item.save();
+			var json = yield item.toJSON({
+				patchBase: patchBase
+			})
+			assert.isUndefined(json.itemType);
+			assert.isUndefined(json.title);
+			assert.equal(json.date, date);
+			assert.isUndefined(json.numPages);
+		})
+	})
 });