Add support for parser object to parserOptions.parser (#196)

* Add support for parser object to `parserOptions.parser`

* update

Author: ota-meshi

README.md

@@ -162,6 +162,28 @@ If you want to switch the parser for each lang, specify the object.
 }
 ```
 
+#### Parser Object
+
+When using JavaScript configuration (`.eslintrc.js`), you can also give the parser object directly.
+
+```js
+const tsParser = require("@typescript-eslint/parser")
+const espree = require("espree")
+
+module.exports = {
+    parser: "svelte-eslint-parser",
+    parserOptions: {
+        // Single parser
+        parser: tsParser,
+        // Multiple parser
+        parser: {
+            js: espree,
+            ts: tsParser,
+        }
+    },
+}
+```
+
 ## :computer: Editor Integrations
 
 ### Visual Studio Code

explorer-v2/build-system/pre-build/webpack.config.js

@@ -74,19 +74,6 @@ export default [
 			'svelte/compiler': '$$inject_svelte_compiler$$',
 			espree: '$$inject_espree$$'
 		},
-		module: {
-			rules: [
-				{
-					test: /\/resolve-parser\.js$/u,
-					loader: 'string-replace-loader',
-					options: {
-						search: 'require\\(name\\)',
-						replace: `__non_webpack_require__(name)`,
-						flags: ''
-					}
-				}
-			]
-		},
 		plugins: [
 			new WrapperPlugin({
 				test: /svelte-eslint-parser\.js/,

explorer-v2/src/lib/VirtualScriptCode.svelte

@@ -4,6 +4,7 @@
 	import MonacoEditor from './MonacoEditor.svelte';
 	import * as svelteEslintParser from 'svelte-eslint-parser';
 
+	let tsParser = undefined;
 	let loaded = false;
 	import('@typescript-eslint/parser')
 		.then((parser) => {
@@ -14,8 +15,8 @@
 						env: {}
 					};
 				}
-				window.require.define('@typescript-eslint/parser', parser);
 			}
+			tsParser = parser;
 		})
 		.then(() => {
 			loaded = true;
@@ -49,7 +50,7 @@
 		const start = Date.now();
 		try {
 			virtualScriptCode = svelteEslintParser.parseForESLint(svelteValue, {
-				parser: '@typescript-eslint/parser'
+				parser: tsParser
 			})._virtualScriptCode;
 		} catch (e) {
 			// eslint-disable-next-line no-console -- Demo

src/context/index.ts

@@ -11,9 +11,10 @@ import type {
 import type ESTree from "estree";
 import { ScriptLetContext } from "./script-let";
 import { LetDirectiveCollections } from "./let-directive-collection";
-import { getParserName } from "../parser/resolve-parser";
+import { getParserForLang } from "../parser/resolve-parser";
 import type { AttributeToken } from "../parser/html";
 import { parseAttributes } from "../parser/html";
+import { maybeTSESLintParserObject } from "../parser/parser-object";
 
 export class ScriptsSourceCode {
   private raw: string;
@@ -202,13 +203,20 @@ export class Context {
     if (!lang) {
       return (this.state.isTypeScript = false);
     }
-    const parserName = getParserName(
+    const parserValue = getParserForLang(
       this.sourceCode.scripts.attrs,
       this.parserOptions?.parser
     );
-    if (parserName === "@typescript-eslint/parser") {
+    if (
+      maybeTSESLintParserObject(parserValue) ||
+      parserValue === "@typescript-eslint/parser"
+    ) {
       return (this.state.isTypeScript = true);
     }
+    if (typeof parserValue !== "string") {
+      return (this.state.isTypeScript = false);
+    }
+    const parserName = parserValue;
     if (parserName.includes("@typescript-eslint/parser")) {
       let targetPath = parserName;
       while (targetPath) {

src/parser/espree.ts

@@ -1,6 +1,6 @@
 import Module from "module";
 import path from "path";
-import type { ESLintCustomParser } from "./resolve-parser";
+import type { BasicParserObject } from "./parser-object";
 
 const createRequire: (filename: string) => (modName: string) => any =
   // Added in v12.2.0
@@ -19,7 +19,7 @@ const createRequire: (filename: string) => (modName: string) => any =
     return mod.exports;
   });
 
-let espreeCache: ESLintCustomParser | null = null;
+let espreeCache: BasicParserObject | null = null;
 
 /** Checks if given path is linter path */
 function isLinterPath(p: string): boolean {
@@ -35,7 +35,7 @@ function isLinterPath(p: string): boolean {
  * Load `espree` from the loaded ESLint.
  * If the loaded ESLint was not found, just returns `require("espree")`.
  */
-export function getEspree(): ESLintCustomParser {
+export function getEspree(): BasicParserObject {
   if (!espreeCache) {
     // Lookup the loaded eslint
     const linterPath = Object.keys(require.cache || {}).find(isLinterPath);

src/parser/parser-object.ts

@@ -0,0 +1,54 @@
+import type { ESLintExtendedProgram, ESLintProgram } from ".";
+import type * as tsESLintParser from "@typescript-eslint/parser";
+type TSESLintParser = typeof tsESLintParser;
+/**
+ * The type of basic ESLint custom parser.
+ * e.g. espree
+ */
+export type BasicParserObject = {
+  parse(code: string, options: any): ESLintProgram;
+  parseForESLint: undefined;
+};
+/**
+ * The type of ESLint custom parser enhanced for ESLint.
+ * e.g. @babel/eslint-parser, @typescript-eslint/parser
+ */
+export type EnhancedParserObject = {
+  parseForESLint(code: string, options: any): ESLintExtendedProgram;
+  parse: undefined;
+};
+
+/**
+ * The type of ESLint (custom) parsers.
+ */
+export type ParserObject = EnhancedParserObject | BasicParserObject;
+
+/** Checks whether given object is ParserObject */
+export function isParserObject(value: unknown): value is ParserObject {
+  return isEnhancedParserObject(value) || isBasicParserObject(value);
+}
+/** Checks whether given object is EnhancedParserObject */
+export function isEnhancedParserObject(
+  value: unknown
+): value is EnhancedParserObject {
+  return Boolean(value && typeof (value as any).parseForESLint === "function");
+}
+/** Checks whether given object is BasicParserObject */
+export function isBasicParserObject(
+  value: unknown
+): value is BasicParserObject {
+  return Boolean(value && typeof (value as any).parse === "function");
+}
+
+/** Checks whether given object is "@typescript-eslint/parser" */
+export function maybeTSESLintParserObject(
+  value: unknown
+): value is TSESLintParser {
+  return (
+    isEnhancedParserObject(value) &&
+    isBasicParserObject(value) &&
+    typeof (value as any).createProgram === "function" &&
+    typeof (value as any).clearCaches === "function" &&
+    typeof (value as any).version === "string"
+  );
+}

src/parser/resolve-parser.ts

@@ -1,29 +1,26 @@
-import type { ESLintExtendedProgram, ESLintProgram } from ".";
 import { getEspree } from "./espree";
-/**
- * The interface of a result of ESLint custom parser.
- */
-export type ESLintCustomParserResult = ESLintProgram | ESLintExtendedProgram;
-/**
- * The interface of ESLint custom parsers.
- */
-export interface ESLintCustomParser {
-  parse(code: string, options: any): ESLintCustomParserResult;
-  parseForESLint?(code: string, options: any): ESLintCustomParserResult;
-}
+import type { ParserObject } from "./parser-object";
+import { isParserObject } from "./parser-object";
+
+type UserOptionParser =
+  | string
+  | ParserObject
+  | Record<string, string | ParserObject | undefined>
+  | undefined;
 
-/** Get parser name */
-export function getParserName(
+/** Get parser for script lang */
+export function getParserForLang(
   attrs: Record<string, string | undefined>,
-  parser: any
-): string {
+  parser: UserOptionParser
+): string | ParserObject {
   if (parser) {
-    if (typeof parser === "string" && parser !== "espree") {
+    if (typeof parser === "string" || isParserObject(parser)) {
       return parser;
-    } else if (typeof parser === "object") {
-      const name = parser[attrs.lang || "js"];
-      if (typeof name === "string") {
-        return getParserName(attrs, name);
+    }
+    if (typeof parser === "object") {
+      const value = parser[attrs.lang || "js"];
+      if (typeof value === "string" || isParserObject(value)) {
+        return value;
       }
     }
   }
@@ -33,12 +30,15 @@ export function getParserName(
 /** Get parser */
 export function getParser(
   attrs: Record<string, string | undefined>,
-  parser: any
-): ESLintCustomParser {
-  const name = getParserName(attrs, parser);
-  if (name !== "espree") {
+  parser: UserOptionParser
+): ParserObject {
+  const parserValue = getParserForLang(attrs, parser);
+  if (isParserObject(parserValue)) {
+    return parserValue;
+  }
+  if (parserValue !== "espree") {
     // eslint-disable-next-line @typescript-eslint/no-require-imports -- ignore
-    return require(name);
+    return require(parserValue);
   }
   return getEspree();
 }

src/parser/script.ts

@@ -3,6 +3,7 @@ import { analyzeScope } from "./analyze-scope";
 import { traverseNodes } from "../traverse";
 import type { ScriptsSourceCode } from "../context";
 import { getParser } from "./resolve-parser";
+import { isEnhancedParserObject } from "./parser-object";
 
 /**
  * Parse for script
@@ -47,8 +48,9 @@ function parseScriptWithoutAnalyzeScope(
 ): ESLintExtendedProgram {
   const parser = getParser(attrs, options.parser);
 
-  const result =
-    parser.parseForESLint?.(vcode, options) ?? parser.parse?.(vcode, options);
+  const result = isEnhancedParserObject(parser)
+    ? parser.parseForESLint(vcode, options)
+    : parser.parse(vcode, options);
 
   if ("ast" in result && result.ast != null) {
     result._virtualScriptCode = vcode;

tests/fixtures/integrations/parser-object-tests/ts-multiple-parser-input.svelte

@@ -0,0 +1,5 @@
+<script lang="ts">
+    export let num: number;
+</script>
+
+{num}

tests/fixtures/integrations/parser-object-tests/ts-multiple-parser-output.json

@@ -0,0 +1 @@
+[]