From f532bf2b495a19540e45d9ed32a6693fca8bceea Mon Sep 17 00:00:00 2001
From: fisker Cheung <lionkay@gmail.com>
Date: Thu, 19 Nov 2020 08:58:56 +0800
Subject: [PATCH] Refactor: Module releated format (#9691)

---
 src/language-js/print/module.js               | 232 +++++++++++++++++-
 src/language-js/printer-estree.js             | 151 ++----------
 .../comments/__snapshots__/jsfmt.spec.js.snap |  12 +-
 3 files changed, 241 insertions(+), 154 deletions(-)

diff --git a/src/language-js/print/module.js b/src/language-js/print/module.js
index 107677341..b1b23a6b0 100644
--- a/src/language-js/print/module.js
+++ b/src/language-js/print/module.js
@@ -1,28 +1,181 @@
 "use strict";
 
 const {
-  builders: { concat, softline, group, indent, join, line, ifBreak },
+  builders: { concat, softline, group, indent, join, line, ifBreak, hardline },
 } = require("../../document");
+const { printDanglingComments } = require("../../main/comments");
 
-const { shouldPrintComma } = require("../utils");
+const {
+  hasDanglingComments,
+  shouldPrintComma,
+  needsHardlineAfterDanglingComment,
+} = require("../utils");
+const { locStart, hasSameLoc } = require("../loc");
 
 /**
  * @typedef {import("../../document").Doc} Doc
  */
 
+function printImportDeclaration(path, options, print) {
+  const node = path.getValue();
+  const semi = options.semi ? ";" : "";
+  /** @type{Doc[]} */
+  const parts = [];
+
+  const { importKind } = node;
+
+  parts.push("import");
+
+  if (importKind && importKind !== "value") {
+    parts.push(" ", importKind);
+  }
+
+  parts.push(
+    printModuleSpecifiers(path, options, print),
+    printModuleSource(path, options, print),
+    printImportAssertions(path, options, print)
+  );
+
+  parts.push(semi);
+
+  return concat(parts);
+}
+
+function printExportDeclaration(path, options, print) {
+  const node = path.getValue();
+  /** @type{Doc[]} */
+  const parts = [];
+
+  const { type, exportKind, declaration } = node;
+  if (type === "DeclareExportDeclaration") {
+    parts.push("declare ");
+  }
+
+  parts.push("export");
+
+  const isDefaultExport = node.default || type === "ExportDefaultDeclaration";
+  if (isDefaultExport) {
+    parts.push(" default");
+  }
+
+  if (hasDanglingComments(node)) {
+    parts.push(
+      " ",
+      printDanglingComments(path, options, /* sameIndent */ true)
+    );
+
+    if (needsHardlineAfterDanglingComment(node)) {
+      parts.push(hardline);
+    }
+  }
+
+  if (declaration) {
+    parts.push(" ", path.call(print, "declaration"));
+  } else {
+    parts.push(
+      exportKind === "type" ? " type" : "",
+      printModuleSpecifiers(path, options, print),
+      printModuleSource(path, options, print),
+      printImportAssertions(path, options, print)
+    );
+  }
+
+  if (shouldExportDeclarationPrintSemi(node, options)) {
+    parts.push(";");
+  }
+
+  return concat(parts);
+}
+
+function printExportAllDeclaration(path, options, print) {
+  const node = path.getValue();
+  let semi = options.semi ? ";" : "";
+  /** @type{Doc[]} */
+  const parts = [];
+
+  const { type, exportKind, exported } = node;
+  if (type === "DeclareExportAllDeclaration") {
+    parts.push("declare ");
+    semi = "";
+  }
+
+  parts.push("export");
+
+  if (exportKind === "type") {
+    parts.push(" type");
+  }
+
+  parts.push(" *");
+
+  if (exported) {
+    parts.push(" as ", path.call(print, "exported"));
+  }
+
+  parts.push(
+    printModuleSource(path, options, print),
+    printImportAssertions(path, options, print),
+    semi
+  );
+
+  return concat(parts);
+}
+
+function shouldExportDeclarationPrintSemi(node, options) {
+  if (!options.semi) {
+    return false;
+  }
+
+  const { type, declaration } = node;
+  const isDefaultExport = node.default || type === "ExportDefaultDeclaration";
+  if (!declaration) {
+    return true;
+  }
+
+  const { type: declarationType } = declaration;
+  if (
+    isDefaultExport &&
+    declarationType !== "ClassDeclaration" &&
+    declarationType !== "FunctionDeclaration" &&
+    declarationType !== "TSInterfaceDeclaration" &&
+    declarationType !== "DeclareClass" &&
+    declarationType !== "DeclareFunction" &&
+    declarationType !== "TSDeclareFunction" &&
+    declarationType !== "EnumDeclaration"
+  ) {
+    return true;
+  }
+  return false;
+}
+
 function printModuleSource(path, options, print) {
   const node = path.getValue();
-  return node.source ? concat([" from ", path.call(print, "source")]) : "";
+
+  if (!node.source) {
+    return "";
+  }
+
+  /** @type{Doc[]} */
+  const parts = [];
+  if (!shouldNotPrintSpecifiers(node, options)) {
+    parts.push(" from");
+  }
+  parts.push(" ", path.call(print, "source"));
+
+  return concat(parts);
 }
 
 function printModuleSpecifiers(path, options, print) {
   const node = path.getValue();
 
+  if (shouldNotPrintSpecifiers(node, options)) {
+    return "";
+  }
+
   /** @type{Doc[]} */
-  const parts = [node.type === "ImportDeclaration" ? " " : ""];
+  const parts = [" "];
 
   if (node.specifiers && node.specifiers.length > 0) {
-    const standalonesSpecifiers = [];
+    const standaloneSpecifiers = [];
     const groupedSpecifiers = [];
 
     path.each((specifierPath) => {
@@ -33,7 +186,7 @@ function printModuleSpecifiers(path, options, print) {
         specifierType === "ImportNamespaceSpecifier" ||
         specifierType === "ImportDefaultSpecifier"
       ) {
-        standalonesSpecifiers.push(print(specifierPath));
+        standaloneSpecifiers.push(print(specifierPath));
       } else if (
         specifierType === "ExportSpecifier" ||
         specifierType === "ImportSpecifier"
@@ -47,16 +200,16 @@ function printModuleSpecifiers(path, options, print) {
       }
     }, "specifiers");
 
-    parts.push(join(", ", standalonesSpecifiers));
+    parts.push(join(", ", standaloneSpecifiers));
 
     if (groupedSpecifiers.length !== 0) {
-      if (standalonesSpecifiers.length !== 0) {
+      if (standaloneSpecifiers.length !== 0) {
         parts.push(", ");
       }
 
       const canBreak =
         groupedSpecifiers.length > 1 ||
-        standalonesSpecifiers.length > 0 ||
+        standaloneSpecifiers.length > 0 ||
         node.specifiers.some((node) => node.comments);
 
       if (canBreak) {
@@ -94,6 +247,23 @@ function printModuleSpecifiers(path, options, print) {
   return concat(parts);
 }
 
+function shouldNotPrintSpecifiers(node, options) {
+  const { type, importKind, source, specifiers } = node;
+
+  if (
+    type !== "ImportDeclaration" ||
+    (Array.isArray(specifiers) && specifiers.length > 0) ||
+    importKind === "type"
+  ) {
+    return false;
+  }
+
+  // TODO: check tokens
+  return !/{\s*}/.test(
+    options.originalText.slice(locStart(node), locStart(source))
+  );
+}
+
 function printImportAssertions(path, options, print) {
   const node = path.getNode();
   if (Array.isArray(node.assertions) && node.assertions.length !== 0) {
@@ -108,8 +278,46 @@ function printImportAssertions(path, options, print) {
   return "";
 }
 
+function printModuleSpecifier(path, options, print) {
+  const node = path.getNode();
+
+  const { type, importKind } = node;
+  /** @type{Doc[]} */
+  const parts = [];
+  if (type === "ImportSpecifier" && importKind) {
+    parts.push(importKind, " ");
+  }
+
+  const isImport = type.startsWith("Import");
+  const leftSideProperty = isImport ? "imported" : "local";
+  const rightSideProperty = isImport ? "local" : "exported";
+  let left = "";
+  let right = "";
+  if (
+    type === "ExportNamespaceSpecifier" ||
+    type === "ImportNamespaceSpecifier"
+  ) {
+    left = "*";
+  } else if (node[leftSideProperty]) {
+    left = path.call(print, leftSideProperty);
+  }
+
+  if (
+    node[rightSideProperty] &&
+    (!node[leftSideProperty] ||
+      // import {a as a} from '.'
+      !hasSameLoc(node[leftSideProperty], node[rightSideProperty]))
+  ) {
+    right = path.call(print, rightSideProperty);
+  }
+
+  parts.push(left, left && right ? " as " : "", right);
+  return concat(parts);
+}
+
 module.exports = {
-  printModuleSource,
-  printModuleSpecifiers,
-  printImportAssertions,
+  printImportDeclaration,
+  printExportDeclaration,
+  printExportAllDeclaration,
+  printModuleSpecifier,
 };
diff --git a/src/language-js/printer-estree.js b/src/language-js/printer-estree.js
index 4657fa348..44065793b 100644
--- a/src/language-js/printer-estree.js
+++ b/src/language-js/printer-estree.js
@@ -103,7 +103,7 @@ const {
   shouldFlatten,
   startsWithNoLookaheadToken,
 } = require("./utils");
-const { locStart, locEnd, hasSameLoc } = require("./loc");
+const { locStart, locEnd } = require("./loc");
 
 const printMemberChain = require("./print/member-chain");
 const printCallArguments = require("./print/call-arguments");
@@ -114,9 +114,10 @@ const {
   printBindExpressionCallee,
 } = require("./print/misc");
 const {
-  printModuleSource,
-  printModuleSpecifiers,
-  printImportAssertions,
+  printImportDeclaration,
+  printExportDeclaration,
+  printExportAllDeclaration,
+  printModuleSpecifier,
 } = require("./print/module");
 const printTernaryOperator = require("./print/ternary");
 const {
@@ -807,93 +808,24 @@ function printPathNoParens(path, options, print, args) {
       }
       return concat(parts);
     }
-    case "ImportSpecifier":
-      if (n.importKind) {
-        parts.push(path.call(print, "importKind"), " ");
-      }
-
-      parts.push(path.call(print, "imported"));
-
-      if (n.local && !hasSameLoc(n.local, n.imported)) {
-        parts.push(" as ", path.call(print, "local"));
-      }
-
-      return concat(parts);
-    case "ExportSpecifier": {
-      parts.push(path.call(print, "local"));
-
-      if (n.exported && !hasSameLoc(n.local, n.exported)) {
-        parts.push(" as ", path.call(print, "exported"));
-      }
-
-      return concat(parts);
-    }
-    case "ImportNamespaceSpecifier":
-      parts.push("* as ");
-      parts.push(path.call(print, "local"));
-      return concat(parts);
-    case "ImportDefaultSpecifier":
-      return path.call(print, "local");
     case "TSExportAssignment":
       return concat(["export = ", path.call(print, "expression"), semi]);
     case "ExportDefaultDeclaration":
     case "ExportNamedDeclaration":
-      return printExportDeclaration(path, options, print);
     case "DeclareExportDeclaration":
-      return concat(["declare ", printExportDeclaration(path, options, print)]);
+      return printExportDeclaration(path, options, print);
     case "ExportAllDeclaration":
-      parts.push("export");
-
-      if (n.exportKind === "type") {
-        parts.push(" type");
-      }
-
-      parts.push(" *");
-
-      if (n.exported) {
-        parts.push(" as ", path.call(print, "exported"));
-      }
-
-      parts.push(
-        printModuleSource(path, options, print),
-        printImportAssertions(path, options, print),
-        semi
-      );
-
-      return concat(parts);
-
+    case "DeclareExportAllDeclaration":
+      return printExportAllDeclaration(path, options, print);
+    case "ImportDeclaration":
+      return printImportDeclaration(path, options, print);
+    case "ImportSpecifier":
+    case "ExportSpecifier":
+    case "ImportNamespaceSpecifier":
     case "ExportNamespaceSpecifier":
-      return concat(["* as ", path.call(print, "exported")]);
+    case "ImportDefaultSpecifier":
     case "ExportDefaultSpecifier":
-      return path.call(print, "exported");
-    case "ImportDeclaration": {
-      parts.push("import");
-
-      if (n.importKind && n.importKind !== "value") {
-        parts.push(" ", n.importKind);
-      }
-
-      if (n.specifiers && n.specifiers.length > 0) {
-        parts.push(printModuleSpecifiers(path, options, print));
-        parts.push(printModuleSource(path, options, print));
-      } else if (
-        (n.importKind && n.importKind === "type") ||
-        // import {} from 'x'
-        /{\s*}/.test(
-          options.originalText.slice(locStart(n), locStart(n.source))
-        )
-      ) {
-        parts.push(" {}", printModuleSource(path, options, print));
-      } else {
-        parts.push(" ", path.call(print, "source"));
-      }
-
-      parts.push(printImportAssertions(path, options, print));
-
-      parts.push(semi);
-
-      return concat(parts);
-    }
+      return printModuleSpecifier(path, options, print);
     case "ImportAttribute":
       return concat([path.call(print, "key"), ": ", path.call(print, "value")]);
     case "Import":
@@ -2350,11 +2282,6 @@ function printPathNoParens(path, options, print, args) {
       ]);
     case "DeclareVariable":
       return printFlowDeclaration(path, ["var ", path.call(print, "id"), semi]);
-    case "DeclareExportAllDeclaration":
-      return concat([
-        "declare export *",
-        printModuleSource(path, options, print),
-      ]);
     case "DeclareOpaqueType":
     case "OpaqueType": {
       parts.push(
@@ -3808,54 +3735,6 @@ function printReturnType(path, print, options) {
   return concat(parts);
 }
 
-function printExportDeclaration(path, options, print) {
-  const decl = path.getValue();
-
-  const semi = options.semi ? ";" : "";
-
-  /** @type{Doc[]} */
-  const parts = ["export "];
-
-  const isDefault = decl.default || decl.type === "ExportDefaultDeclaration";
-
-  if (isDefault) {
-    parts.push("default ");
-  }
-
-  parts.push(
-    comments.printDanglingComments(path, options, /* sameIndent */ true)
-  );
-
-  if (needsHardlineAfterDanglingComment(decl)) {
-    parts.push(hardline);
-  }
-
-  if (decl.declaration) {
-    parts.push(path.call(print, "declaration"));
-
-    if (
-      isDefault &&
-      decl.declaration.type !== "ClassDeclaration" &&
-      decl.declaration.type !== "FunctionDeclaration" &&
-      decl.declaration.type !== "TSInterfaceDeclaration" &&
-      decl.declaration.type !== "DeclareClass" &&
-      decl.declaration.type !== "DeclareFunction" &&
-      decl.declaration.type !== "TSDeclareFunction" &&
-      decl.declaration.type !== "EnumDeclaration"
-    ) {
-      parts.push(semi);
-    }
-  } else {
-    parts.push(decl.exportKind === "type" ? "type " : "");
-    parts.push(printModuleSpecifiers(path, options, print));
-    parts.push(printModuleSource(path, options, print));
-    parts.push(printImportAssertions(path, options, print));
-    parts.push(semi);
-  }
-
-  return concat(parts);
-}
-
 function printFlowDeclaration(path, parts) {
   const parentExportDecl = getParentExportDeclaration(path);
 
diff --git a/tests/js/comments/__snapshots__/jsfmt.spec.js.snap b/tests/js/comments/__snapshots__/jsfmt.spec.js.snap
index 46bb3bfb7..aec6bbbce 100644
--- a/tests/js/comments/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/js/comments/__snapshots__/jsfmt.spec.js.snap
@@ -1175,7 +1175,7 @@ function d() {
 }
 new Thing(/* dangling */)
 Thing(/* dangling */)
-export /* dangling */{}
+export /* dangling */ {}
 
 ================================================================================
 `;
@@ -1213,7 +1213,7 @@ function d() {
 }
 new Thing(/* dangling */);
 Thing(/* dangling */);
-export /* dangling */{};
+export /* dangling */ {};
 
 ================================================================================
 `;
@@ -1476,9 +1476,9 @@ export {
 
 =====================================output=====================================
 export //comment
-{}
+ {}
 
-export /* comment */{}
+export /* comment */ {}
 
 const foo = ""
 export {
@@ -1532,9 +1532,9 @@ export {
 
 =====================================output=====================================
 export //comment
-{};
+ {};
 
-export /* comment */{};
+export /* comment */ {};
 
 const foo = "";
 export {