Add options.plugins schema validation, ensure apply method is present. Add tests

lib/webpack.js

@@ -30,14 +30,6 @@ function webpack(options, callback) {
 		compiler.options = options;
 		new NodeEnvironmentPlugin().apply(compiler);
 		if(options.plugins && Array.isArray(options.plugins)) {
-			// sanity check the options plugins
-			options.plugins.forEach((plugin, index) => {
-				const typeofPlugin = typeof plugin;
-				if((typeofPlugin !== "object" && typeofPlugin !== "function") || Array.isArray(plugin)) {
-					let failureValue = Array.isArray(plugin) ? "array" : typeofPlugin;
-					throw new Error("Invalid plugin provided at index " + index + ": " + failureValue + " given");
-				}
-			});
 			compiler.apply.apply(compiler, options.plugins);
 		}
 		compiler.applyPlugins("environment");

schemas/webpackOptionsSchema.json

@@ -1,6 +1,34 @@
 {
   "additionalProperties": false,
   "definitions": {
+    "common.pluginFunction": {
+      "description": "Compiler or Resolver Plugin instance of Function",
+      "instanceof": "Function",
+      "properties": {
+        "apply": {
+          "description": "The run point of the plugin, required method.",
+          "instanceof": "Function"
+        }
+      },
+      "additionalProperties": true,
+      "required": [
+        "apply"
+      ]
+    },
+    "common.pluginObject": {
+      "description": "Compiler or Resolver Plugin instance of Function",
+      "type": "object",
+      "properties": {
+        "apply": {
+          "description": "The run point of the plugin, required method.",
+          "instanceof": "Function"
+        }
+      },
+      "additionalProperties": true,
+      "required": [
+        "apply"
+      ]
+    },
     "common.arrayOfStringOrStringArrayValues": {
       "items": {
         "description": "string or array of strings",
@@ -600,7 +628,18 @@
         },
         "plugins": {
           "description": "Plugins for the resolver",
-          "type": "array"
+          "type": "array",
+          "items": {
+            "description": "Plugin of type object or instanceof Function",
+            "anyOf": [
+              {
+                "$ref": "#/definitions/common.pluginObject"
+              },
+              {
+                "$ref": "#/definitions/common.pluginFunction"
+              }
+            ]
+          }
         },
         "resolver": {
           "description": "Custom resolver"
@@ -1178,7 +1217,18 @@
     },
     "plugins": {
       "description": "Add additional plugins to the compiler.",
-      "type": "array"
+      "type": "array",
+      "items": {
+        "description": "Plugin of type object or instanceof Function",
+        "anyOf": [
+          {
+            "$ref": "#/definitions/common.pluginObject"
+          },
+          {
+            "$ref": "#/definitions/common.pluginFunction"
+          }
+        ]
+      }
     },
     "profile": {
       "description": "Capture timing information for each module.",

test/Validation.test.js

@@ -255,6 +255,74 @@ describe("Validation", () => {
 				" - configuration.stats should be one of these:"
 			);
 		}
+	}, {
+		name: "Invalid plugin provided: bool",
+		config: {
+			entry: "foo.js",
+			plugins: [
+				false
+			]
+		},
+		test(err) {
+			err.message.should.startWith("Invalid configuration object.");
+			err.message.split("\n").slice(1)[0].should.be.eql(
+				" - configuration.plugins[0] should be one of these:"
+			);
+		}
+	}, {
+		name: "Invalid plugin provided: array",
+		config: {
+			entry: "foo.js",
+			plugins: [
+				[]
+			]
+		},
+		test(err) {
+			err.message.should.startWith("Invalid configuration object.");
+			err.message.split("\n").slice(1)[0].should.be.eql(
+				" - configuration.plugins[0] should be one of these:"
+			);
+		}
+	}, {
+		name: "Invalid plugin provided: string",
+		config: {
+			entry: "foo.js",
+			plugins: ["abc123"]
+		},
+		test(err) {
+			err.message.should.startWith("Invalid configuration object.");
+			err.message.split("\n").slice(1)[0].should.be.eql(
+				" - configuration.plugins[0] should be one of these:"
+			);
+		}
+	}, {
+		name: "Invalid plugin provided: int",
+		config: {
+			entry: "foo.js",
+			plugins: [
+				12
+			]
+		},
+		test(err) {
+			err.message.should.startWith("Invalid configuration object.");
+			err.message.split("\n").slice(1)[0].should.be.eql(
+				" - configuration.plugins[0] should be one of these:"
+			);
+		}
+	}, {
+		name: "Invalid plugin provided: object without apply function",
+		config: {
+			entry: "foo.js",
+			plugins: [
+				new function() {}
+			]
+		},
+		test(err) {
+			err.message.should.startWith("Invalid configuration object.");
+			err.message.split("\n").slice(1)[0].should.be.eql(
+				" - configuration.plugins[0] should be one of these:"
+			);
+		}
 	}];
 
 	testCases.forEach((testCase) => {