wip-Emit import call expression for commonjs

src/compiler/factory.ts

@@ -1644,6 +1644,7 @@ namespace ts {
             if (node.resolvedTypeReferenceDirectiveNames !== undefined) updated.resolvedTypeReferenceDirectiveNames = node.resolvedTypeReferenceDirectiveNames;
             if (node.imports !== undefined) updated.imports = node.imports;
             if (node.moduleAugmentations !== undefined) updated.moduleAugmentations = node.moduleAugmentations;
+            if (node.containsDynamicImport !== undefined) updated.containsDynamicImport = node.containsDynamicImport;
             return updateNode(updated, node);
         }
 

src/compiler/parser.ts

@@ -461,7 +461,7 @@ namespace ts {
     }
 
     export function isExternalModule(file: SourceFile): boolean {
-        return file.externalModuleIndicator !== undefined;
+        return file.externalModuleIndicator !== undefined || file.containsDynamicImport;
     }
 
     // Produces a new SourceFile for the 'newText' provided. The 'textChangeRange' parameter
@@ -2778,6 +2778,7 @@ namespace ts {
                 case SyntaxKind.SlashToken:
                 case SyntaxKind.SlashEqualsToken:
                 case SyntaxKind.Identifier:
+                case SyntaxKind.ImportKeyword:
                     return true;
                 default:
                     return isIdentifier();
@@ -3698,6 +3699,7 @@ namespace ts {
                 if (importCall.specifier.kind === SyntaxKind.StringLiteral) {
                     (sourceFile.imports || (sourceFile.imports = [])).push(importCall.specifier as StringLiteral);
                 }
+                sourceFile.containsDynamicImport = true;
                 return importCall;
             }
             const expression = token() === SyntaxKind.SuperKeyword ? parseSuperExpression() : parseMemberExpressionOrHigher();

src/compiler/transformers/module/module.ts

@@ -482,12 +482,35 @@ namespace ts {
                     return visitEndOfDeclarationMarker(<EndOfDeclarationMarker>node);
 
                 default:
-                    // This visitor does not descend into the tree, as export/import statements
-                    // are only transformed at the top level of a file.
-                    return node;
+                    return visitEachChild(node, visitor, context);
             }
         }
 
+        function visitor(node: Node): VisitResult<Node> {
+            // This visitor does not need to descend into the tree if there is no dynamic import,
+            // as export/import statements are only transformed at the top level of a file.
+            if (!currentSourceFile.containsDynamicImport) {
+                return node;
+            }
+
+            switch (node.kind) {
+                case SyntaxKind.ImportCallExpression:
+                    return visitImportCallExpression(<ImportCallExpression>node);
+                default:
+                    return visitEachChild(node, visitor, context);
+            }
+        }
+
+        function visitImportCallExpression(node: ImportCallExpression): Expression{
+            return createCall(
+                createPropertyAccess(
+                    createCall(/*expression*/ createPropertyAccess(createIdentifier("Promise"), "resolve"), /*typeArguments*/ undefined, /*argumentsArray*/ []),
+                    "then"),
+                /*typeArguments*/ undefined,
+                [ createArrowFunction(/*modifiers*/ undefined, /*typeParameters*/ undefined, /*parameters*/ undefined, /*type*/ undefined, createToken(SyntaxKind.EqualsGreaterThanToken), createCall(createIdentifier("require"), /*typeArguments*/ undefined, [node.specifier]))]
+            );
+        }
+
         /**
          * Visits an ImportDeclaration node.
          *
@@ -780,7 +803,7 @@ namespace ts {
                                 node.asteriskToken,
                                 getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
                                 /*typeParameters*/ undefined,
-                                node.parameters,
+                                visitNodes(node.parameters, visitor),
                                 /*type*/ undefined,
                                 node.body
                             ),
@@ -822,7 +845,7 @@ namespace ts {
                                 visitNodes(node.modifiers, modifierVisitor, isModifier),
                                 getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
                                 /*typeParameters*/ undefined,
-                                node.heritageClauses,
+                                visitNodes(node.heritageClauses, visitor),
                                 node.members
                             ),
                             node
@@ -884,7 +907,7 @@ namespace ts {
                 }
             }
             else {
-                statements = append(statements, node);
+                statements = append(statements, visitEachChild(node, visitor, context));
             }
 
             if (hasAssociatedEndOfDeclarationMarker(node)) {
@@ -907,7 +930,7 @@ namespace ts {
         function transformInitializedVariable(node: VariableDeclaration): Expression {
             if (isBindingPattern(node.name)) {
                 return flattenDestructuringAssignment(
-                    node,
+                    visitNode(node, visitor),
                     /*visitor*/ undefined,
                     context,
                     FlattenLevel.All,
@@ -924,7 +947,7 @@ namespace ts {
                         ),
                         /*location*/ node.name
                     ),
-                    node.initializer
+                    visitNode(node.initializer, visitor)
                 );
             }
         }

src/compiler/types.ts

@@ -2282,6 +2282,7 @@ namespace ts {
         /* @internal */ moduleAugmentations: LiteralExpression[];
         /* @internal */ patternAmbientModules?: PatternAmbientModule[];
         /* @internal */ ambientModuleNames: string[];
+        /* @internal */ containsDynamicImport?: boolean;
     }
 
     export interface Bundle extends Node {

tests/cases/conformance/es2018/dynamicImport/importCallExpressionInCJS1.ts

@@ -0,0 +1,11 @@
+// @module: commonjs
+// @target: esnext
+// @filename: 0.ts
+export function foo() { return "foo"; }
+
+// @filename: 1.ts
+import("./0");
+var p1 = import("./0");
+p1.then(zero => {
+    return zero.foo();
+});

tests/cases/conformance/es2018/dynamicImport/importCallExpressionInCJS2.ts

@@ -0,0 +1,19 @@
+// @module: commonjs
+// @target: esnext
+// @filename: 0.ts
+export function foo() { return "foo"; }
+
+// @filename: 1.ts
+export function backup() { return "backup"; }
+
+// @filename: 2.ts
+async function compute(promise: Promise<any>) {
+    let j = await promise;
+    if (!j) {
+        j = await import("./1");
+        return j.backup();
+    }
+    return j.foo();
+}
+
+compute(import("./0"));