Add rule for testing the files property in package.json - fixes #3

source/lib/compiler.ts

@@ -1,4 +1,6 @@
-import {createProgram, getPreEmitDiagnostics, ScriptTarget, ModuleResolutionKind} from 'typescript';
+import * as path from 'path';
+import {createProgram, getPreEmitDiagnostics, ScriptTarget, ModuleResolutionKind, flattenDiagnosticMessageText} from 'typescript';
+import {Diagnostic, Context} from './interfaces';
 
 const loadConfig = () => {
 	return {
@@ -8,15 +10,38 @@ const loadConfig = () => {
 };
 
 /**
- * Get a list of diagnostics for the given file.
+ * Get a list of TypeScript diagnostics within the current context.
  *
- * @param fileName - Name of the file run the diagnosis on.
+ * @param context - The context object.
  * @returns List of diagnostics
  */
-export const getDiagnostics = (fileName: string) => {
+export const getDiagnostics = (context: Context): Diagnostic[] => {
 	const compilerOptions = loadConfig();
 
+	const fileName = path.join(context.cwd, context.testFile);
+
 	const program = createProgram([fileName], compilerOptions);
 
-	return getPreEmitDiagnostics(program);
+	// Retrieve the TypeScript compiler diagnostics
+	const diagnostics = getPreEmitDiagnostics(program);
+
+	const result: Diagnostic[] = [];
+
+	for (const diagnostic of diagnostics) {
+		if (!diagnostic.file) {
+			continue;
+		}
+
+		const position = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start as number);
+
+		result.push({
+			fileName: diagnostic.file.fileName,
+			message: flattenDiagnosticMessageText(diagnostic.messageText, '\n'),
+			severity: 'error',
+			line: position.line + 1,
+			column: position.character
+		});
+	}
+
+	return result;
 };

source/lib/formatter.ts

@@ -1,5 +1,5 @@
-import {flattenDiagnosticMessageText, Diagnostic} from 'typescript';
 import * as formatter from 'eslint-formatter-pretty';
+import {Diagnostic} from './interfaces';
 
 /**
  * Format the TypeScript diagnostics to a human readable output.
@@ -11,32 +11,21 @@ export default (diagnostics: Diagnostic[]) => {
 	const fileMap = new Map<string>();
 
 	for (const diagnostic of diagnostics) {
-		if (!diagnostic.file) {
-			continue;
-		}
-
-		let entry = fileMap.get(diagnostic.file.fileName);
+		let entry = fileMap.get(diagnostic.fileName);
 
 		if (!entry) {
 			entry = {
-				filePath: diagnostic.file.fileName,
+				filePath: diagnostic.fileName,
 				errorCount: 0,
 				warningCount: 0,
 				messages: []
 			};
 
-			fileMap.set(diagnostic.file.fileName, entry);
+			fileMap.set(diagnostic.fileName, entry);
 		}
 
-		const position = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start as number);
-
 		entry.errorCount++;
-		entry.messages.push({
-			message: flattenDiagnosticMessageText(diagnostic.messageText, '\n'),
-			severity: 'error',
-			line: position.line + 1,
-			column: position.character
-		});
+		entry.messages.push(diagnostic);
 	}
 
 	return formatter(Array.from(fileMap.values()));

source/lib/index.ts

@@ -1,7 +1,9 @@
 import * as path from 'path';
 import * as readPkgUp from 'read-pkg-up';
 import * as pathExists from 'path-exists';
-import {getDiagnostics} from './compiler';
+import {getDiagnostics as getTSDiagnostics} from './compiler';
+import getCustomDiagnostics from './rules';
+import {Context} from './interfaces';
 
 interface Options {
 	cwd: string;
@@ -48,5 +50,15 @@ export default async (options: Options = {cwd: process.cwd()}) => {
 
 	const testFile = await findTestFile(typingsFile, options);
 
-	return getDiagnostics(path.join(options.cwd, testFile));
+	const context: Context = {
+		cwd: options.cwd,
+		pkg,
+		typingsFile,
+		testFile
+	};
+
+	return [
+		...getCustomDiagnostics(context),
+		...getTSDiagnostics(context)
+	];
 };

source/lib/interfaces.ts

@@ -0,0 +1,14 @@
+export interface Context {
+	cwd: string;
+	pkg: any;
+	typingsFile: string;
+	testFile: string;
+}
+
+export interface Diagnostic {
+	fileName: string;
+	message: string;
+	severity: 'error' | 'warning';
+	line?: number;
+	column?: number;
+}

source/lib/rules/files-property.ts

@@ -0,0 +1,30 @@
+import * as path from 'path';
+import * as fs from 'fs';
+import {Context, Diagnostic} from '../interfaces';
+import {getJSONPropertyPosition} from '../utils';
+
+/**
+ * Rule which enforces the typings file to be present in the `files` list in `package.json`.
+ *
+ * @param context - The context object.
+ * @returns A list of custom diagnostics.
+ */
+export default (context: Context): Diagnostic[] => {
+	const {pkg, typingsFile} = context;
+	const typingsFileName = path.basename(typingsFile);
+
+	if (!Array.isArray(pkg.files) || pkg.files.indexOf(typingsFileName) !== -1) {
+		return [];
+	}
+
+	const content = fs.readFileSync(path.join(context.cwd, 'package.json'), 'utf8');
+
+	return [
+		{
+			fileName: 'package.json',
+			message: 'TypeScript type definition is not part of the `files` list.',
+			severity: 'error',
+			...getJSONPropertyPosition(content, 'files')
+		}
+	];
+};

source/lib/rules/index.ts

@@ -0,0 +1,25 @@
+import filesProperty from './files-property';
+import {Diagnostic, Context} from '../interfaces';
+
+type RuleFunction = (context: Context) => Diagnostic[];
+
+// List of custom rules
+const rules = new Set<RuleFunction>([
+	filesProperty
+]);
+
+/**
+ * Get a list of custom diagnostics within the current context.
+ *
+ * @param context - The context object.
+ * @returns List of diagnostics
+ */
+export default (context: Context) => {
+	const diagnostics: Diagnostic[] = [];
+
+	for (const rule of rules) {
+		diagnostics.push(...rule(context));
+	}
+
+	return diagnostics;
+};

source/lib/utils.ts

@@ -0,0 +1,22 @@
+/**
+ * Retrieve the line and column position of a property in a JSON document.
+ *
+ * @param content - Content of the JSON document.
+ * @param property - Property to search for.
+ * @returns Position of the property or `undefined` if the property could not be found.
+ */
+export const getJSONPropertyPosition = (content: string, property: string) => {
+	const match = new RegExp(`([\\s\\S]*?)"${property}"`, 'm').exec(content);
+
+	if (!match) {
+		return;
+	}
+
+	const lines = match[0].split('\n');
+	const lastLine = lines[lines.length - 1];
+
+	return {
+		line: lines.length,
+		column: lastLine ? lastLine.indexOf(`"${property}"`) : 0
+	};
+};

source/test/fixtures/no-files/index.d.ts

@@ -0,0 +1,6 @@
+declare const one: {
+	(foo: string, bar: string): string;
+	(foo: number, bar: number): number;
+};
+
+export default one;

source/test/fixtures/no-files/index.js

@@ -0,0 +1,3 @@
+module.exports.default = (foo, bar) => {
+	return foo + bar;
+};

source/test/fixtures/no-files/index.test-d.ts

@@ -0,0 +1,5 @@
+import {expectType} from '../../..';
+import one from '.';
+
+expectType<string>(one('foo', 'bar'));
+expectType<number>(one(1, 2));

source/test/fixtures/no-files/package.json

@@ -0,0 +1,6 @@
+{
+	"name": "foo",
+	"files": [
+		"index.js"
+	]
+}

source/test/fixtures/success/package.json

@@ -1,3 +1,7 @@
 {
-	"name": "foo"
+	"name": "foo",
+	"files": [
+		"index.js",
+		"index.d.ts"
+	]
 }

source/test/test.ts

@@ -14,7 +14,21 @@ test('return diagnostics', async t => {
 	const diagnostics = await m({cwd: path.join(__dirname, 'fixtures/failure')});
 
 	t.true(diagnostics.length === 1);
-	t.is(diagnostics[0].messageText, 'Argument of type \'number\' is not assignable to parameter of type \'string\'.');
+	t.is(diagnostics[0].message, 'Argument of type \'number\' is not assignable to parameter of type \'string\'.');
+});
+
+test('fail if typings file is not part of `files` list', async t => {
+	const diagnostics = await m({cwd: path.join(__dirname, 'fixtures/no-files')});
+
+	t.deepEqual(diagnostics, [
+		{
+			fileName: 'package.json',
+			message: 'TypeScript type definition is not part of the `files` list.',
+			severity: 'error',
+			line: 3,
+			column: 1
+		}
+	]);
 });
 
 test('return no diagnostics', async t => {