Add possibility to create empty subsets

This feature is necessary because it might be possible to create schemas that have only readable fields. In this case, schema.writableFields() should just work without throwing an error.
peerigon · Jun 16, 2016 · f6a4a02 · f6a4a02
1 parent a8d8874
commit f6a4a02
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Showing 2 changed files with 12 additions and 24 deletions.
diff --git a/lib/Schema.js b/lib/Schema.js
@@ -51,10 +51,6 @@ Schema.prototype.only = function (key1, key2, key3) {
         fields = slice.call(arguments);
     }
 
-    if (fields.length === 0) {
-        throw new Error("Cannot create a subset of the schema with no keys");
-    }
-
     subset.fields = fields;
 
     return subset;
@@ -79,10 +75,6 @@ Schema.prototype.except = function (key1, key2, key3) {
         fields = slice.call(arguments);
     }
 
-    if (fields.length === this.fields.length) {
-        throw new Error("Cannot create a subset of the schema with no keys");
-    }
-
     subset.fields = this.fields.filter(function (value) {
         return fields.indexOf(value) === -1;
     });

diff --git a/test/Schema.test.js b/test/Schema.test.js
@@ -140,10 +140,9 @@ describe("Schema", function () {
                 expect(subset.fields).to.eql(["name", "age"]);
             });
 
-            it("should throw an error if no keys are given", function () {
-                expect(function () {
-                    schema.only();
-                }).to.throw("Cannot create a subset of the schema with no keys");
+            it("should be possible to create schemas with no fields", function () {
+                subset = schema.only();
+                expect(subset.fields).to.eql([]);
             });
 
         });
@@ -156,10 +155,9 @@ describe("Schema", function () {
                 expect(subset.fields).to.eql(["name", "age"]);
             });
 
-            it("should throw an error if no keys are given", function () {
-                expect(function () {
-                    schema.only([]);
-                }).to.throw("Cannot create a subset of the schema with no keys");
+            it("should be possible to create schemas with no fields", function () {
+                subset = schema.only([]);
+                expect(subset.fields).to.eql([]);
             });
 
         });
@@ -192,10 +190,9 @@ describe("Schema", function () {
                 expect(subset.fields).to.eql(["name"]);
             });
 
-            it("should throw an error if no keys are given", function () {
-                expect(function () {
-                    schema.except.apply(schema, schema.fields);
-                }).to.throw("Cannot create a subset of the schema with no keys");
+            it("should be possible to exclude all fields", function () {
+                subset = schema.except.apply(schema, schema.fields);
+                expect(subset.fields).to.eql([]);
             });
 
         });
@@ -208,10 +205,9 @@ describe("Schema", function () {
                 expect(subset.fields).to.eql(["name", "age"]);
             });
 
-            it("should throw an error if no keys are given", function () {
-                expect(function () {
-                    schema.except(schema.fields);
-                }).to.throw("Cannot create a subset of the schema with no keys");
+            it("should be possible to exclude all fields", function () {
+                subset = schema.except(schema.fields);
+                expect(subset.fields).to.eql([]);
             });
 
         });