Playground: doc explorer (#10183)

changelog_unreleased/api/10183.md

@@ -0,0 +1,3 @@
+#### "Doc Explorer" mode for the Playground (#10183 by @thorn0)
+
+Switch the `parser` option to the special `doc-explorer` value to play with Prettier's intermediate representation and see how it's printed with different options.

docs/technical-details.md

@@ -9,4 +9,6 @@ The basic idea is that the printer takes an AST and returns an intermediate repr
 
 This means that most of the logic of printing an AST involves generating an abstract representation of the output involving certain commands. For example, `["(", line, arg, line, ")"]` would represent a concatenation of opening parens, an argument, and closing parens. But if that doesn’t fit on one line, the printer can break where `line` is specified.
 
+The [Playground](https://prettier.io/playground) has a special mode for exploring how Prettier’s intermediate representation is printed. To get there, open the sidebar (the "Show options" button) and set the `parser` option to the special value `doc-explorer`.
+
 More (rough) details can be found in [commands.md](https://github.com/prettier/prettier/blob/main/commands.md).

netlify.toml

@@ -4,3 +4,7 @@
 [build.environment]
   NODE_VERSION = "lts/*"
   YARN_VERSION = "1.22.15"
+[[headers]]
+  for = "/worker.js"
+  [headers.values]
+    Content-Security-Policy = "default-src 'self'; script-src 'self' 'unsafe-eval'"

src/main/parser.js

@@ -96,7 +96,7 @@ function parse(text, opts) {
     }
 
     /* istanbul ignore next */
-    throw error.stack;
+    throw error;
   }
 }
 

website/playground/Playground.js

@@ -67,10 +67,13 @@ class Playground extends React.Component {
       options.parser = "babel";
     }
 
-    const content = original.content || getCodeSample(options.parser);
+    const codeSample = getCodeSample(options.parser);
+    const content = original.content || codeSample;
+    const needsClickForFirstRun =
+      options.parser === "doc-explorer" && content !== codeSample;
     const selection = {};
 
-    this.state = { content, options, selection };
+    this.state = { content, options, selection, needsClickForFirstRun };
 
     this.handleOptionValueChange = this.handleOptionValueChange.bind(this);
 
@@ -80,14 +83,10 @@ class Playground extends React.Component {
     this.setSelection = (selection) => this.setState({ selection });
     this.setSelectionAsRange = () => {
       const { selection, content, options } = this.state;
-      const { head, anchor } = selection;
-      const range = [head, anchor].map(
-        ({ ch, line }) =>
-          content.split("\n").slice(0, line).join("\n").length +
-          ch +
-          (line ? 1 : 0)
+      const [rangeStart, rangeEnd] = util.convertSelectionToRange(
+        selection,
+        content
       );
-      const [rangeStart, rangeEnd] = range.sort((a, b) => a - b);
       const updatedOptions = { ...options, rangeStart, rangeEnd };
       if (rangeStart === rangeEnd) {
         delete updatedOptions.rangeStart;
@@ -103,6 +102,8 @@ class Playground extends React.Component {
     this.rangeEndOption = props.availableOptions.find(
       (opt) => opt.name === "rangeEnd"
     );
+
+    this.handleInputPanelFormat = this.handleInputPanelFormat.bind(this);
   }
 
   componentDidUpdate(_, prevState) {
@@ -131,6 +132,10 @@ class Playground extends React.Component {
           ? getCodeSample(options.parser)
           : state.content;
 
+      if (option.name === "parser") {
+        state.needsClickForFirstRun = false;
+      }
+
       return { options, content };
     });
   }
@@ -158,6 +163,30 @@ class Playground extends React.Component {
     });
   }
 
+  handleInputPanelFormat() {
+    if (this.state.options.parser !== "doc-explorer") {
+      return;
+    }
+
+    const { content, selection } = this.state;
+
+    return this.props.worker
+      .format(content, {
+        parser: "__js_expression",
+        cursorOffset: util.convertSelectionToRange(selection, content)[0],
+      })
+      .then(({ error, formatted, cursorOffset }) => {
+        if (error) {
+          return;
+        }
+
+        return {
+          value: formatted,
+          cursor: util.convertOffsetToPosition(cursorOffset, formatted),
+        };
+      });
+  }
+
   render() {
     const { worker, version } = this.props;
     const { content, options } = this.state;
@@ -171,6 +200,7 @@ class Playground extends React.Component {
       <EditorState>
         {(editorState) => (
           <PrettierFormat
+            enabled={!this.state.needsClickForFirstRun}
             worker={worker}
             code={content}
             options={options}
@@ -259,9 +289,10 @@ class Playground extends React.Component {
                           checked={editorState.showSecondFormat}
                           onChange={editorState.toggleSecondFormat}
                         />
-                        {editorState.showDoc && debug.doc && (
+                        {editorState.showDoc && (
                           <ClipboardButton
                             copy={() => this.getMarkdown({ doc: debug.doc })}
+                            disabled={!debug.doc}
                           >
                             Copy doc
                           </ClipboardButton>
@@ -284,6 +315,7 @@ class Playground extends React.Component {
                           overlayEnd={options.rangeEnd}
                           onChange={this.setContent}
                           onSelectionChange={this.setSelection}
+                          onFormat={this.handleInputPanelFormat}
                         />
                       ) : null}
                       {editorState.showAst ? (
@@ -302,11 +334,36 @@ class Playground extends React.Component {
                         />
                       ) : null}
                       {editorState.showOutput ? (
-                        <OutputPanel
-                          mode={util.getCodemirrorMode(options.parser)}
-                          value={formatted}
-                          ruler={options.printWidth}
-                        />
+                        this.state.needsClickForFirstRun ? (
+                          <div className="editor disabled-output-panel">
+                            <div className="explanation">
+                              <code>doc-explorer</code> involves running code
+                              provided by users.
+                            </div>
+                            <div className="explanation">
+                              To stay on the safe side and prevent abuse, an
+                              explicit user action is required when a direct
+                              link to a <code>doc-explorer</code> playground is
+                              opened.
+                            </div>
+                            <div className="explanation">
+                              Click the button below to start the playground.
+                            </div>
+                            <Button
+                              onClick={() =>
+                                this.setState({ needsClickForFirstRun: false })
+                              }
+                            >
+                              Start
+                            </Button>
+                          </div>
+                        ) : (
+                          <OutputPanel
+                            mode={util.getCodemirrorMode(options.parser)}
+                            value={formatted}
+                            ruler={options.printWidth}
+                          />
+                        )
                       ) : null}
                       {editorState.showSecondFormat ? (
                         <OutputPanel

website/playground/PrettierFormat.js

@@ -12,6 +12,7 @@ export default class PrettierFormat extends React.Component {
 
   componentDidUpdate(prevProps) {
     for (const key of [
+      "enabled",
       "code",
       "options",
       "debugAst",
@@ -28,6 +29,7 @@ export default class PrettierFormat extends React.Component {
 
   format() {
     const {
+      enabled,
       worker,
       code,
       options,
@@ -37,6 +39,10 @@ export default class PrettierFormat extends React.Component {
       reformat,
     } = this.props;
 
+    if (!enabled) {
+      return;
+    }
+
     worker
       .format(code, options, { ast, doc, comments, reformat })
       .then((result) => this.setState(result));

website/playground/WorkerApi.js

@@ -32,7 +32,7 @@ export default function WorkerApi(source) {
     getMetadata() {
       return postMessage({ type: "meta" });
     },
-    format(code, options, debug) {
+    format(code, options, debug = {}) {
       return postMessage({ type: "format", code, options, debug });
     },
     postMessage,

website/playground/codeSamples.js

@@ -308,6 +308,24 @@ export default function getCodeSamples(parser) {
         "  </body>",
         "</HTML>",
       ].join("\n");
+    case "doc-explorer":
+      return [
+        "group([",
+        '  "(*",',
+        "  indent([",
+        "    line,",
+        '    "Prettier:",',
+        "    line,",
+        '    "Opinionated,",',
+        "    line,",
+        '    "Code,",',
+        "    line,",
+        '    "Formatter",',
+        "  ]),",
+        "  line,",
+        '  "*)",',
+        "])",
+      ].join("\n");
     default:
       return "";
   }

website/playground/markdown.js

@@ -41,6 +41,7 @@ function getMarkdownSyntax(options) {
     case "acorn":
     case "espree":
     case "meriyah":
+    case "doc-explorer":
       return "jsx";
     case "babel-ts":
     case "typescript":

website/playground/panels.js

@@ -19,6 +19,7 @@ class CodeMirrorPanel extends React.Component {
     delete options.rulerColor;
     delete options.value;
     delete options.onChange;
+    delete options.onFormat;
 
     options.rulers = [makeRuler(this.props)];
 
@@ -26,6 +27,12 @@ class CodeMirrorPanel extends React.Component {
       options.gutters = ["CodeMirror-linenumbers", "CodeMirror-foldgutter"];
     }
 
+    if (this.props.onFormat) {
+      options.extraKeys = {
+        "Shift-Alt-F": this.handleFormat.bind(this),
+      };
+    }
+
     this._codeMirror = CodeMirror.fromTextArea(
       this._textareaRef.current,
       options
@@ -112,6 +119,17 @@ class CodeMirrorPanel extends React.Component {
     }
   }
 
+  handleFormat() {
+    const result = this.props.onFormat();
+    if (!result) {
+      return;
+    }
+    Promise.resolve(result).then(({ value, cursor }) => {
+      this.props.onChange(value);
+      this._codeMirror.setCursor(cursor);
+    });
+  }
+
   render() {
     return (
       <div className="editor input">

website/playground/util.js

@@ -95,6 +95,30 @@ export function getAstAutoFold(parser) {
   }
 }
 
+export function convertSelectionToRange({ head, anchor }, content) {
+  const lines = content.split("\n");
+  return [head, anchor]
+    .map(
+      ({ ch, line }) =>
+        lines.slice(0, line).join("\n").length + ch + (line ? 1 : 0)
+    )
+    .sort((a, b) => a - b);
+}
+
+export function convertOffsetToPosition(offset, content) {
+  let line = 0;
+  let ch = 0;
+  for (let i = 0; i < offset && i <= content.length; i++) {
+    if (content[i] === "\n") {
+      line++;
+      ch = 0;
+    } else {
+      ch++;
+    }
+  }
+  return { line, ch };
+}
+
 /**
  * Copied from https://github.com/prettier/prettier/blob/6fe21780115cf5f74f83876d64b03a727fbab220/src/cli/utils.js#L6-L27
  * @template Obj

website/static/separate-css/playground.css

@@ -112,6 +112,25 @@ header h1 {
   border-bottom: 1px solid #ddd;
 }
 
+.disabled-output-panel {
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  gap: 15px;
+  text-align: center;
+}
+
+.disabled-output-panel .explanation {
+  font-size: 16px;
+  max-width: 400px;
+  color: darkred;
+}
+
+.disabled-output-panel .btn {
+  font-size: 22px;
+  padding: 10px 20px;
+}
+
 /* display as 2x2 grid */
 @media (min-width: 800px) {
   .options-container {
@@ -258,7 +277,7 @@ input[type="number"] {
   border-color: #c8e1ff;
 }
 
-.btn:hover {
+.btn:hover:enabled {
   background-color: #e6ebf1;
   background-image: linear-gradient(to bottom, #f0f3f6, #dce3ec);
   border-color: #afb1b2;
@@ -271,6 +290,10 @@ input[type="number"] {
   box-shadow: inset 0 0.15em 0.3em rgba(27, 31, 35, 0.15);
 }
 
+.btn:disabled {
+  color: #afb1b2;
+}
+
 .tooltip {
   position: absolute;
   z-index: 6;

website/static/worker.js

@@ -30,6 +30,25 @@ for (const file in parsersLocation) {
   }
 }
 
+const docExplorerPlugin = {
+  parsers: {
+    "doc-explorer": {
+      parse: (text) =>
+        new Function(
+          `{ ${Object.keys(prettier.doc.builders)} }`,
+          `const result = (${text || "''"}\n); return result;`
+        )(prettier.doc.builders),
+      astFormat: "doc-explorer",
+    },
+  },
+  printers: {
+    "doc-explorer": {
+      print: (path) => path.getValue(),
+    },
+  },
+  languages: [{ name: "doc-explorer", parsers: ["doc-explorer"] }],
+};
+
 self.onmessage = function (event) {
   self.postMessage({
     uid: event.data.uid,
@@ -45,6 +64,8 @@ function serializeAst(ast) {
         ? { name: value.name, message: value.message, ...value }
         : typeof value === "bigint"
         ? `BigInt('${String(value)}')`
+        : typeof value === "symbol"
+        ? String(value)
         : value,
     2
   );
@@ -58,6 +79,7 @@ function handleMessage(message) {
         JSON.stringify(
           prettier.getSupportInfo({
             showUnreleased: true,
+            plugins: [docExplorerPlugin],
           })
         )
       ),
@@ -72,13 +94,15 @@ function handleMessage(message) {
     delete options.doc;
     delete options.output2;
 
-    const plugins = [{ parsers }];
+    const plugins = [{ parsers }, docExplorerPlugin];
     options.plugins = plugins;
 
     const formatResult = formatCode(message.code, options);
 
     const response = {
       formatted: formatResult.formatted,
+      cursorOffset: formatResult.cursorOffset,
+      error: formatResult.error,
       debug: {
         ast: null,
         doc: null,
@@ -111,10 +135,10 @@ function handleMessage(message) {
       try {
         response.debug.doc = prettier.__debug.formatDoc(
           prettier.__debug.printToDoc(message.code, options),
-          { parser: "babel", plugins }
+          { plugins }
         );
-      } catch (e) {
-        response.debug.doc = String(e);
+      } catch {
+        response.debug.doc = "";
       }
     }
 
@@ -142,10 +166,23 @@ function formatCode(text, options) {
   } catch (e) {
     if (e.constructor && e.constructor.name === "SyntaxError") {
       // Likely something wrong with the user's code
-      return { formatted: String(e) };
+      return { formatted: String(e), error: true };
     }
     // Likely a bug in Prettier
     // Provide the whole stack for debugging
-    return { formatted: e.stack || String(e) };
+    return { formatted: stringifyError(e), error: true };
   }
 }
+
+function stringifyError(e) {
+  const stringified = String(e);
+  if (typeof e.stack !== "string") {
+    return stringified;
+  }
+  if (e.stack.includes(stringified)) {
+    // Chrome
+    return e.stack;
+  }
+  // Firefox
+  return stringified + "\n" + e.stack;
+}