acorn 8, esm, mocha (#205)

* remove husky

* adopt esm, mocha

* acorn 8

* restore .db.sql test

* simpler serialization

* re-enable reference tests

* add private field test

* restore peekId

* yarn upgrade

* remove unused rollup plugins

* remove sublime project

* test Markdown interpolation

Author: mbostock

.eslintignore

@@ -1,3 +1,2 @@
 dist/
-test/
-tap-snapshots/
+test/input/

.eslintrc.json

@@ -2,17 +2,17 @@
   "extends": "eslint:recommended",
   "parserOptions": {
     "sourceType": "module",
-    "ecmaVersion": 2018
+    "ecmaVersion": 2020
   },
   "env": {
     "es6": true,
     "node": true
   },
   "rules": {
-    "semi": 2,
     "no-cond-assign": 0,
-    "no-process-env": 2,
     "no-var": 2,
+    "comma-dangle": ["error", "never"],
+    "semi": [2, "always"],
     "quotes": ["error", "double", {"allowTemplateLiterals": true}]
   }
 }

.github/eslint.json

@@ -0,0 +1,18 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "eslint-compact",
+      "pattern": [
+        {
+          "regexp": "^(.+):\\sline\\s(\\d+),\\scol\\s(\\d+),\\s(Error|Warning|Info)\\s-\\s(.+)\\s\\((.+)\\)$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "severity": 4,
+          "message": 5,
+          "code": 6
+        }
+      ]
+    }
+  ]
+}

.github/workflows/nodejs.yml

@@ -1,26 +1,30 @@
-name: Node CI
+# https://help.github.com/actions/language-and-framework-guides/using-nodejs-with-github-actions
 
-on: [push]
+name: Node.js CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
 
 jobs:
   build:
 
+    runs-on: ubuntu-latest
+
     strategy:
       matrix:
-        os: [ubuntu-latest]
-        node-version: [10.x, 12.x]
-
-    runs-on: ${{ matrix.os }}
+        node-version: [14.x]
 
     steps:
-    - uses: actions/checkout@v1
+    - uses: actions/checkout@v2
     - name: Use Node.js ${{ matrix.node-version }}
       uses: actions/setup-node@v1
       with:
         node-version: ${{ matrix.node-version }}
-    - name: yarn install and test
-      run: |
-        yarn install --frozen-lockfile
-        yarn test
-      env:
-        CI: true
+    - run: yarn --frozen-lockfile
+    - run: |
+        echo ::add-matcher::.github/eslint.json
+        yarn run eslint . --format=compact
+    - run: yarn test

.gitignore

@@ -1,7 +1,3 @@
-*.sublime-workspace
 .DS_Store
-.nyc_output
 dist/
-node_modules
-npm-debug.log
-.idea
+node_modules/

README.md

@@ -1,7 +1,5 @@
 # @observablehq/parser
 
-[![Node CI](https://github.com/observablehq/parser/workflows/Node%20CI/badge.svg)](https://github.com/observablehq/parser/actions?workflow=Node+CI)
-
 To parse a cell:
 
 ```js
@@ -423,15 +421,11 @@ Injecting a view injects both the view symbol (`viewof foo`) and the value symbo
 
 ## API Reference
 
-<a href="#parseCell" name="parseCell">#</a> <b>parseCell</b>(<i>input</i>[, <i>options</i>]) [<>](https://github.com/observablehq/parser/blob/master/src/parse.js "Source")
+<a href="#parseCell" name="parseCell">#</a> <b>parseCell</b>(<i>input</i>[, <i>options</i>]) [<>](https://github.com/observablehq/parser/blob/main/src/parse.js "Source")
 
 Returns a [cell](#cell).
 
-<a href="#parseModule" name="parseModule">#</a> <b>parseModule</b>(<i>input</i>[, <i>options</i>]) [<>](https://github.com/observablehq/parser/blob/master/src/parse.js "Source")
-
-Returns a [program](#program).
-
-<a href="#peekId" name="peekId">#</a> <b>peekId</b>(<i>input</i>) [<>](https://github.com/observablehq/parser/blob/master/src/parse.js "Source")
+<a href="#peekId" name="peekId">#</a> <b>peekId</b>(<i>input</i>) [<>](https://github.com/observablehq/parser/blob/main/src/peek.js "Source")
 
 Tries to find the ID of a cell given a snippet of its contents, and returns it as a string if found.
 

package.json

@@ -1,44 +1,52 @@
 {
   "name": "@observablehq/parser",
+  "description": "An Acorn parser for Observable JavaScript",
   "version": "5.0.0",
-  "license": "ISC",
-  "main": "dist/parser.min.js",
-  "module": "src/index.js",
   "author": {
     "name": "Observable, Inc.",
     "url": "https://observablehq.com"
   },
+  "license": "ISC",
+  "type": "module",
+  "main": "src/index.js",
+  "module": "src/index.js",
+  "jsdelivr": "dist/parser.min.js",
+  "unpkg": "dist/parser.min.js",
+  "exports": {
+    "umd": "./dist/parser.min.js",
+    "default": "./src/index.js"
+  },
   "repository": {
     "type": "git",
     "url": "https://github.com/observablehq/parser.git"
   },
+  "files": [
+    "dist/**/*.js",
+    "src/**/*.js"
+  ],
+  "engines": {
+    "node": ">=14.5.0"
+  },
   "scripts": {
-    "test": "eslint . && tap 'test/**/*-test.js'",
-    "snapshot": "TAP_SNAPSHOT=1 tap 'test/**/*-test.js'",
+    "test": "mkdir -p test/output && mocha -r module-alias/register 'test/**/*-test.js' && eslint src test",
     "prepublishOnly": "rm -rf dist && rollup -c",
     "postpublish": "git push && git push --tags"
   },
-  "husky": {
-    "hooks": {
-      "pre-commit": "yarn test"
-    }
+  "_moduleAliases": {
+    "@observablehq/parser": "./src/index.js"
   },
   "dependencies": {
-    "acorn": "^7.1.1",
-    "acorn-walk": "^7.0.0"
+    "acorn": "8",
+    "acorn-walk": "8"
   },
   "devDependencies": {
-    "eslint": "^6.7.2",
-    "esm": "^3.0.84",
-    "rollup": "^2.26.11",
-    "rollup-plugin-commonjs": "^10.1.0",
-    "rollup-plugin-node-resolve": "^5.0.0",
-    "rollup-plugin-terser": "^7.0.2",
-    "tap": "^14.10.2",
-    "husky": "^3.1.0"
+    "eslint": "8",
+    "mocha": "9",
+    "module-alias": "2",
+    "rollup": "2",
+    "rollup-plugin-terser": "7"
   },
-  "files": [
-    "dist/**/*.js",
-    "src/**/*.js"
-  ]
+  "publishConfig": {
+    "access": "public"
+  }
 }

parser.sublime-project

@@ -1,5 +1,3 @@
-import commonjs from "rollup-plugin-commonjs";
-import node from "rollup-plugin-node-resolve";
 import {terser} from "rollup-plugin-terser";
 import * as meta from "./package.json";
 
@@ -9,8 +7,6 @@ export default [
 {
   input: "src/index.js",
   plugins: [
-    node(),
-    commonjs(),
     terser({
       output: {preamble: copyright},
       mangle: {reserved: ["RequireError"]}

rollup.config.js

@@ -1,2 +1,3 @@
-export {parseCell, peekId, CellParser, TemplateCellParser, parseModule, ModuleParser} from "./parse.js";
+export {parseCell, CellParser, TemplateCellParser} from "./parse.js";
+export {peekId} from "./peek.js";
 export {default as walk} from "./walk.js";

src/index.js

@@ -7,11 +7,6 @@ const SCOPE_FUNCTION = 2;
 const SCOPE_ASYNC = 4;
 const SCOPE_GENERATOR = 8;
 
-const STATE_START = Symbol("start");
-const STATE_MODIFIER = Symbol("modifier");
-const STATE_FUNCTION = Symbol("function");
-const STATE_NAME = Symbol("name");
-
 export function parseCell(input, {tag, raw, globals, ...options} = {}) {
   let cell;
   // Parse empty input as JavaScript to keep ensure resulting ast
@@ -31,79 +26,9 @@ export function parseCell(input, {tag, raw, globals, ...options} = {}) {
   return cell;
 }
 
-/*
-                       ┌─────┐
-           ┌───────────│START│─function|class
-           │           └─────┘             │
-viewof|mutable|async      │                ▼
-           │              │           ┌────────┐     ┌─┐
-           ▼              │           │FUNCTION│◀───▶│*│
-      ┌────────┐          │           └────────┘     └─┘
-      │MODIFIER│          │                │
-      └────────┘        name             name
-           │              │                │
-           └──name─┐      │                ▼
-                   ▼      │         ┌─────────────┐
-              ┌────────┐  │         │FUNCTION_NAME│
-              │  NAME  │◀─┘         └─────────────┘
-              └────────┘
-                   │
-                   =
-                   ▼
-              ┌────────┐
-              │   EQ   │
-              └────────┘
-*/
-
-export function peekId(input) {
-  let state = STATE_START;
-  let name;
-  try {
-    for (const token of Parser.tokenizer(input, {ecmaVersion: 11})) {
-      switch (state) {
-        case STATE_START:
-        case STATE_MODIFIER: {
-          if (token.type === tt.name) {
-            if (
-              state === STATE_START &&
-              (token.value === "viewof" ||
-                token.value === "mutable" ||
-                token.value === "async")
-            ) {
-              state = STATE_MODIFIER;
-              continue;
-            }
-            state = STATE_NAME;
-            name = token;
-            continue;
-          }
-          if (token.type === tt._function || token.type === tt._class) {
-            state = STATE_FUNCTION;
-            continue;
-          }
-          break;
-        }
-        case STATE_NAME: {
-          if (token.type === tt.eq) return name.value;
-          break;
-        }
-        case STATE_FUNCTION: {
-          if (token.type === tt.star) continue;
-          if (token.type === tt.name && token.end < input.length)
-            return token.value;
-          break;
-        }
-      }
-      return;
-    }
-  } catch (ignore) {
-    return;
-  }
-}
-
 export class CellParser extends Parser {
   constructor(options, ...args) {
-    super(Object.assign({ecmaVersion: 12}, options), ...args);
+    super(Object.assign({ecmaVersion: 13}, options), ...args);
   }
   enterScope(flags) {
     if (flags & SCOPE_FUNCTION) ++this.O_function;
@@ -161,7 +86,7 @@ export class CellParser extends Parser {
       } else {
         node.local = node.imported;
       }
-      this.checkLVal(node.local, "let");
+      this.checkLValSimple(node.local, "let");
       if (identifiers.has(node.local.name)) {
         this.raise(node.local.start, `Identifier '${node.local.name}' has already been declared`);
       }
@@ -271,8 +196,8 @@ export class CellParser extends Parser {
     }
     return super.checkUnreserved(node);
   }
-  checkLVal(expr, bindingType, checkClashes) {
-    return super.checkLVal(
+  checkLValSimple(expr, bindingType, checkClashes) {
+    return super.checkLValSimple(
       expr.type === "MutableExpression" ? expr.id : expr,
       bindingType,
       checkClashes
@@ -367,28 +292,6 @@ function readTemplateToken() {
   return this.finishToken(tt.invalidTemplate, this.input.slice(this.start, this.pos));
 }
 
-export function parseModule(input, {globals} = {}) {
-  const program = ModuleParser.parse(input);
-  for (const cell of program.cells) {
-    parseReferences(cell, input, globals);
-    parseFeatures(cell, input, globals);
-  }
-  return program;
-}
-
-export class ModuleParser extends CellParser {
-  parseTopLevel(node) {
-    if (!node.cells) node.cells = [];
-    while (this.type !== tt.eof) {
-      const cell = this.parseCell(this.startNode());
-      cell.input = this.input;
-      node.cells.push(cell);
-    }
-    this.next();
-    return this.finishNode(node, "Program");
-  }
-}
-
 export class CellTagParser extends Parser {
   constructor(options, ...args) {
     super(Object.assign({ecmaVersion: 12}, options), ...args);