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Copy pathsystem.ts
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1826 lines (1625 loc) · 78.9 KB
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/// <reference path="../../factory.ts" />
/// <reference path="../../visitor.ts" />
/// <reference path="../destructuring.ts" />
/*@internal*/
namespace ts {
export function transformSystemModule(context: TransformationContext) {
interface DependencyGroup {
name: StringLiteral;
externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[];
}
const {
startLexicalEnvironment,
endLexicalEnvironment,
hoistVariableDeclaration
} = context;
const compilerOptions = context.getCompilerOptions();
const resolver = context.getEmitResolver();
const host = context.getEmitHost();
const previousOnSubstituteNode = context.onSubstituteNode;
const previousOnEmitNode = context.onEmitNode;
context.onSubstituteNode = onSubstituteNode;
context.onEmitNode = onEmitNode;
context.enableSubstitution(SyntaxKind.Identifier); // Substitutes expression identifiers for imported symbols.
context.enableSubstitution(SyntaxKind.BinaryExpression); // Substitutes assignments to exported symbols.
context.enableSubstitution(SyntaxKind.PrefixUnaryExpression); // Substitutes updates to exported symbols.
context.enableSubstitution(SyntaxKind.PostfixUnaryExpression); // Substitutes updates to exported symbols.
context.enableEmitNotification(SyntaxKind.SourceFile); // Restore state when substituting nodes in a file.
const moduleInfoMap: ExternalModuleInfo[] = []; // The ExternalModuleInfo for each file.
const deferredExports: Statement[][] = []; // Exports to defer until an EndOfDeclarationMarker is found.
const exportFunctionsMap: Identifier[] = []; // The export function associated with a source file.
const noSubstitutionMap: boolean[][] = []; // Set of nodes for which substitution rules should be ignored for each file.
let currentSourceFile: SourceFile; // The current file.
let moduleInfo: ExternalModuleInfo; // ExternalModuleInfo for the current file.
let exportFunction: Identifier; // The export function for the current file.
let contextObject: Identifier; // The context object for the current file.
let hoistedStatements: Statement[];
let enclosingBlockScopedContainer: Node;
let noSubstitution: boolean[]; // Set of nodes for which substitution rules should be ignored.
return transformSourceFile;
/**
* Transforms the module aspects of a SourceFile.
*
* @param node The SourceFile node.
*/
function transformSourceFile(node: SourceFile) {
if (node.isDeclarationFile || !(isEffectiveExternalModule(node, compilerOptions) || node.transformFlags & TransformFlags.ContainsDynamicImport)) {
return node;
}
const id = getOriginalNodeId(node);
currentSourceFile = node;
enclosingBlockScopedContainer = node;
// System modules have the following shape:
//
// System.register(['dep-1', ... 'dep-n'], function(exports) {/* module body function */})
//
// The parameter 'exports' here is a callback '<T>(name: string, value: T) => T' that
// is used to publish exported values. 'exports' returns its 'value' argument so in
// most cases expressions that mutate exported values can be rewritten as:
//
// expr -> exports('name', expr)
//
// The only exception in this rule is postfix unary operators,
// see comment to 'substitutePostfixUnaryExpression' for more details
// Collect information about the external module and dependency groups.
moduleInfo = moduleInfoMap[id] = collectExternalModuleInfo(node, resolver, compilerOptions);
// Make sure that the name of the 'exports' function does not conflict with
// existing identifiers.
exportFunction = createUniqueName("exports");
exportFunctionsMap[id] = exportFunction;
contextObject = createUniqueName("context");
// Add the body of the module.
const dependencyGroups = collectDependencyGroups(moduleInfo.externalImports);
const moduleBodyBlock = createSystemModuleBody(node, dependencyGroups);
const moduleBodyFunction = createFunctionExpression(
/*modifiers*/ undefined,
/*asteriskToken*/ undefined,
/*name*/ undefined,
/*typeParameters*/ undefined,
[
createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, exportFunction),
createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, contextObject)
],
/*type*/ undefined,
moduleBodyBlock
);
// Write the call to `System.register`
// Clear the emit-helpers flag for later passes since we'll have already used it in the module body
// So the helper will be emit at the correct position instead of at the top of the source-file
const moduleName = tryGetModuleNameFromFile(node, host, compilerOptions);
const dependencies = createArrayLiteral(map(dependencyGroups, dependencyGroup => dependencyGroup.name));
const updated = setEmitFlags(
updateSourceFileNode(
node,
setTextRange(
createNodeArray([
createStatement(
createCall(
createPropertyAccess(createIdentifier("System"), "register"),
/*typeArguments*/ undefined,
moduleName
? [moduleName, dependencies, moduleBodyFunction]
: [dependencies, moduleBodyFunction]
)
)
]),
node.statements
)
), EmitFlags.NoTrailingComments);
if (!(compilerOptions.outFile || compilerOptions.out)) {
moveEmitHelpers(updated, moduleBodyBlock, helper => !helper.scoped);
}
if (noSubstitution) {
noSubstitutionMap[id] = noSubstitution;
noSubstitution = undefined;
}
currentSourceFile = undefined;
moduleInfo = undefined;
exportFunction = undefined;
contextObject = undefined;
hoistedStatements = undefined;
enclosingBlockScopedContainer = undefined;
return aggregateTransformFlags(updated);
}
/**
* Collects the dependency groups for this files imports.
*
* @param externalImports The imports for the file.
*/
function collectDependencyGroups(externalImports: (ImportDeclaration | ImportEqualsDeclaration | ExportDeclaration)[]) {
const groupIndices = createMap<number>();
const dependencyGroups: DependencyGroup[] = [];
for (const externalImport of externalImports) {
const externalModuleName = getExternalModuleNameLiteral(externalImport, currentSourceFile, host, resolver, compilerOptions);
if (externalModuleName) {
const text = externalModuleName.text;
const groupIndex = groupIndices.get(text);
if (groupIndex !== undefined) {
// deduplicate/group entries in dependency list by the dependency name
dependencyGroups[groupIndex].externalImports.push(externalImport);
}
else {
groupIndices.set(text, dependencyGroups.length);
dependencyGroups.push({
name: externalModuleName,
externalImports: [externalImport]
});
}
}
}
return dependencyGroups;
}
/**
* Adds the statements for the module body function for the source file.
*
* @param node The source file for the module.
* @param dependencyGroups The grouped dependencies of the module.
*/
function createSystemModuleBody(node: SourceFile, dependencyGroups: DependencyGroup[]) {
// Shape of the body in system modules:
//
// function (exports) {
// <list of local aliases for imports>
// <hoisted variable declarations>
// <hoisted function declarations>
// return {
// setters: [
// <list of setter function for imports>
// ],
// execute: function() {
// <module statements>
// }
// }
// <temp declarations>
// }
//
// i.e:
//
// import {x} from 'file1'
// var y = 1;
// export function foo() { return y + x(); }
// console.log(y);
//
// Will be transformed to:
//
// function(exports) {
// function foo() { return y + file_1.x(); }
// exports("foo", foo);
// var file_1, y;
// return {
// setters: [
// function(v) { file_1 = v }
// ],
// execute(): function() {
// y = 1;
// console.log(y);
// }
// };
// }
const statements: Statement[] = [];
// We start a new lexical environment in this function body, but *not* in the
// body of the execute function. This allows us to emit temporary declarations
// only in the outer module body and not in the inner one.
startLexicalEnvironment();
// Add any prologue directives.
const ensureUseStrict = getStrictOptionValue(compilerOptions, "alwaysStrict") || (!compilerOptions.noImplicitUseStrict && isExternalModule(currentSourceFile));
const statementOffset = addPrologue(statements, node.statements, ensureUseStrict, sourceElementVisitor);
// var __moduleName = context_1 && context_1.id;
statements.push(
createVariableStatement(
/*modifiers*/ undefined,
createVariableDeclarationList([
createVariableDeclaration(
"__moduleName",
/*type*/ undefined,
createLogicalAnd(
contextObject,
createPropertyAccess(contextObject, "id")
)
)
])
)
);
// Visit the synthetic external helpers import declaration if present
visitNode(moduleInfo.externalHelpersImportDeclaration, sourceElementVisitor, isStatement);
// Visit the statements of the source file, emitting any transformations into
// the `executeStatements` array. We do this *before* we fill the `setters` array
// as we both emit transformations as well as aggregate some data used when creating
// setters. This allows us to reduce the number of times we need to loop through the
// statements of the source file.
const executeStatements = visitNodes(node.statements, sourceElementVisitor, isStatement, statementOffset);
// Emit early exports for function declarations.
addRange(statements, hoistedStatements);
// We emit hoisted variables early to align roughly with our previous emit output.
// Two key differences in this approach are:
// - Temporary variables will appear at the top rather than at the bottom of the file
addRange(statements, endLexicalEnvironment());
const exportStarFunction = addExportStarIfNeeded(statements);
const moduleObject = createObjectLiteral([
createPropertyAssignment("setters",
createSettersArray(exportStarFunction, dependencyGroups)
),
createPropertyAssignment("execute",
createFunctionExpression(
/*modifiers*/ undefined,
/*asteriskToken*/ undefined,
/*name*/ undefined,
/*typeParameters*/ undefined,
/*parameters*/ [],
/*type*/ undefined,
createBlock(executeStatements, /*multiLine*/ true)
)
)
]);
moduleObject.multiLine = true;
statements.push(createReturn(moduleObject));
return createBlock(statements, /*multiLine*/ true);
}
/**
* Adds an exportStar function to a statement list if it is needed for the file.
*
* @param statements A statement list.
*/
function addExportStarIfNeeded(statements: Statement[]) {
if (!moduleInfo.hasExportStarsToExportValues) {
return;
}
// when resolving exports local exported entries/indirect exported entries in the module
// should always win over entries with similar names that were added via star exports
// to support this we store names of local/indirect exported entries in a set.
// this set is used to filter names brought by star expors.
// local names set should only be added if we have anything exported
if (!moduleInfo.exportedNames && moduleInfo.exportSpecifiers.size === 0) {
// no exported declarations (export var ...) or export specifiers (export {x})
// check if we have any non star export declarations.
let hasExportDeclarationWithExportClause = false;
for (const externalImport of moduleInfo.externalImports) {
if (externalImport.kind === SyntaxKind.ExportDeclaration && externalImport.exportClause) {
hasExportDeclarationWithExportClause = true;
break;
}
}
if (!hasExportDeclarationWithExportClause) {
// we still need to emit exportStar helper
const exportStarFunction = createExportStarFunction(/*localNames*/ undefined);
statements.push(exportStarFunction);
return exportStarFunction.name;
}
}
const exportedNames: ObjectLiteralElementLike[] = [];
if (moduleInfo.exportedNames) {
for (const exportedLocalName of moduleInfo.exportedNames) {
if (exportedLocalName.escapedText === "default") {
continue;
}
// write name of exported declaration, i.e 'export var x...'
exportedNames.push(
createPropertyAssignment(
createLiteral(exportedLocalName),
createTrue()
)
);
}
}
for (const externalImport of moduleInfo.externalImports) {
if (externalImport.kind !== SyntaxKind.ExportDeclaration) {
continue;
}
const exportDecl = <ExportDeclaration>externalImport;
if (!exportDecl.exportClause) {
// export * from ...
continue;
}
for (const element of exportDecl.exportClause.elements) {
// write name of indirectly exported entry, i.e. 'export {x} from ...'
exportedNames.push(
createPropertyAssignment(
createLiteral(idText(element.name || element.propertyName)),
createTrue()
)
);
}
}
const exportedNamesStorageRef = createUniqueName("exportedNames");
statements.push(
createVariableStatement(
/*modifiers*/ undefined,
createVariableDeclarationList([
createVariableDeclaration(
exportedNamesStorageRef,
/*type*/ undefined,
createObjectLiteral(exportedNames, /*multiline*/ true)
)
])
)
);
const exportStarFunction = createExportStarFunction(exportedNamesStorageRef);
statements.push(exportStarFunction);
return exportStarFunction.name;
}
/**
* Creates an exportStar function for the file, with an optional set of excluded local
* names.
*
* @param localNames An optional reference to an object containing a set of excluded local
* names.
*/
function createExportStarFunction(localNames: Identifier | undefined) {
const exportStarFunction = createUniqueName("exportStar");
const m = createIdentifier("m");
const n = createIdentifier("n");
const exports = createIdentifier("exports");
let condition: Expression = createStrictInequality(n, createLiteral("default"));
if (localNames) {
condition = createLogicalAnd(
condition,
createLogicalNot(
createCall(
createPropertyAccess(localNames, "hasOwnProperty"),
/*typeArguments*/ undefined,
[n]
)
)
);
}
return createFunctionDeclaration(
/*decorators*/ undefined,
/*modifiers*/ undefined,
/*asteriskToken*/ undefined,
exportStarFunction,
/*typeParameters*/ undefined,
[createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, m)],
/*type*/ undefined,
createBlock([
createVariableStatement(
/*modifiers*/ undefined,
createVariableDeclarationList([
createVariableDeclaration(
exports,
/*type*/ undefined,
createObjectLiteral([])
)
])
),
createForIn(
createVariableDeclarationList([
createVariableDeclaration(n, /*type*/ undefined)
]),
m,
createBlock([
setEmitFlags(
createIf(
condition,
createStatement(
createAssignment(
createElementAccess(exports, n),
createElementAccess(m, n)
)
)
),
EmitFlags.SingleLine
)
])
),
createStatement(
createCall(
exportFunction,
/*typeArguments*/ undefined,
[exports]
)
)
], /*multiline*/ true)
);
}
/**
* Creates an array setter callbacks for each dependency group.
*
* @param exportStarFunction A reference to an exportStarFunction for the file.
* @param dependencyGroups An array of grouped dependencies.
*/
function createSettersArray(exportStarFunction: Identifier, dependencyGroups: DependencyGroup[]) {
const setters: Expression[] = [];
for (const group of dependencyGroups) {
// derive a unique name for parameter from the first named entry in the group
const localName = forEach(group.externalImports, i => getLocalNameForExternalImport(i, currentSourceFile));
const parameterName = localName ? getGeneratedNameForNode(localName) : createUniqueName("");
const statements: Statement[] = [];
for (const entry of group.externalImports) {
const importVariableName = getLocalNameForExternalImport(entry, currentSourceFile);
switch (entry.kind) {
case SyntaxKind.ImportDeclaration:
if (!(<ImportDeclaration>entry).importClause) {
// 'import "..."' case
// module is imported only for side-effects, no emit required
break;
}
// falls through
case SyntaxKind.ImportEqualsDeclaration:
Debug.assert(importVariableName !== undefined);
// save import into the local
statements.push(
createStatement(
createAssignment(importVariableName, parameterName)
)
);
break;
case SyntaxKind.ExportDeclaration:
Debug.assert(importVariableName !== undefined);
if ((<ExportDeclaration>entry).exportClause) {
// export {a, b as c} from 'foo'
//
// emit as:
//
// exports_({
// "a": _["a"],
// "c": _["b"]
// });
const properties: PropertyAssignment[] = [];
for (const e of (<ExportDeclaration>entry).exportClause.elements) {
properties.push(
createPropertyAssignment(
createLiteral(idText(e.name)),
createElementAccess(
parameterName,
createLiteral(idText(e.propertyName || e.name))
)
)
);
}
statements.push(
createStatement(
createCall(
exportFunction,
/*typeArguments*/ undefined,
[createObjectLiteral(properties, /*multiline*/ true)]
)
)
);
}
else {
// export * from 'foo'
//
// emit as:
//
// exportStar(foo_1_1);
statements.push(
createStatement(
createCall(
exportStarFunction,
/*typeArguments*/ undefined,
[parameterName]
)
)
);
}
break;
}
}
setters.push(
createFunctionExpression(
/*modifiers*/ undefined,
/*asteriskToken*/ undefined,
/*name*/ undefined,
/*typeParameters*/ undefined,
[createParameter(/*decorators*/ undefined, /*modifiers*/ undefined, /*dotDotDotToken*/ undefined, parameterName)],
/*type*/ undefined,
createBlock(statements, /*multiLine*/ true)
)
);
}
return createArrayLiteral(setters, /*multiLine*/ true);
}
//
// Top-level Source Element Visitors
//
/**
* Visit source elements at the top-level of a module.
*
* @param node The node to visit.
*/
function sourceElementVisitor(node: Node): VisitResult<Node> {
switch (node.kind) {
case SyntaxKind.ImportDeclaration:
return visitImportDeclaration(<ImportDeclaration>node);
case SyntaxKind.ImportEqualsDeclaration:
return visitImportEqualsDeclaration(<ImportEqualsDeclaration>node);
case SyntaxKind.ExportDeclaration:
// ExportDeclarations are elided as they are handled via
// `appendExportsOfDeclaration`.
return undefined;
case SyntaxKind.ExportAssignment:
return visitExportAssignment(<ExportAssignment>node);
default:
return nestedElementVisitor(node);
}
}
/**
* Visits an ImportDeclaration node.
*
* @param node The node to visit.
*/
function visitImportDeclaration(node: ImportDeclaration): VisitResult<Statement> {
let statements: Statement[];
if (node.importClause) {
hoistVariableDeclaration(getLocalNameForExternalImport(node, currentSourceFile));
}
if (hasAssociatedEndOfDeclarationMarker(node)) {
// Defer exports until we encounter an EndOfDeclarationMarker node
const id = getOriginalNodeId(node);
deferredExports[id] = appendExportsOfImportDeclaration(deferredExports[id], node);
}
else {
statements = appendExportsOfImportDeclaration(statements, node);
}
return singleOrMany(statements);
}
/**
* Visits an ImportEqualsDeclaration node.
*
* @param node The node to visit.
*/
function visitImportEqualsDeclaration(node: ImportEqualsDeclaration): VisitResult<Statement> {
Debug.assert(isExternalModuleImportEqualsDeclaration(node), "import= for internal module references should be handled in an earlier transformer.");
let statements: Statement[];
hoistVariableDeclaration(getLocalNameForExternalImport(node, currentSourceFile));
if (hasAssociatedEndOfDeclarationMarker(node)) {
// Defer exports until we encounter an EndOfDeclarationMarker node
const id = getOriginalNodeId(node);
deferredExports[id] = appendExportsOfImportEqualsDeclaration(deferredExports[id], node);
}
else {
statements = appendExportsOfImportEqualsDeclaration(statements, node);
}
return singleOrMany(statements);
}
/**
* Visits an ExportAssignment node.
*
* @param node The node to visit.
*/
function visitExportAssignment(node: ExportAssignment): VisitResult<Statement> {
if (node.isExportEquals) {
// Elide `export=` as it is illegal in a SystemJS module.
return undefined;
}
const expression = visitNode(node.expression, destructuringAndImportCallVisitor, isExpression);
const original = node.original;
if (original && hasAssociatedEndOfDeclarationMarker(original)) {
// Defer exports until we encounter an EndOfDeclarationMarker node
const id = getOriginalNodeId(node);
deferredExports[id] = appendExportStatement(deferredExports[id], createIdentifier("default"), expression, /*allowComments*/ true);
}
else {
return createExportStatement(createIdentifier("default"), expression, /*allowComments*/ true);
}
}
/**
* Visits a FunctionDeclaration, hoisting it to the outer module body function.
*
* @param node The node to visit.
*/
function visitFunctionDeclaration(node: FunctionDeclaration): VisitResult<Statement> {
if (hasModifier(node, ModifierFlags.Export)) {
hoistedStatements = append(hoistedStatements,
updateFunctionDeclaration(
node,
node.decorators,
visitNodes(node.modifiers, modifierVisitor, isModifier),
node.asteriskToken,
getDeclarationName(node, /*allowComments*/ true, /*allowSourceMaps*/ true),
/*typeParameters*/ undefined,
visitNodes(node.parameters, destructuringAndImportCallVisitor, isParameterDeclaration),
/*type*/ undefined,
visitNode(node.body, destructuringAndImportCallVisitor, isBlock)));
}
else {
hoistedStatements = append(hoistedStatements, visitEachChild(node, destructuringAndImportCallVisitor, context));
}
if (hasAssociatedEndOfDeclarationMarker(node)) {
// Defer exports until we encounter an EndOfDeclarationMarker node
const id = getOriginalNodeId(node);
deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
}
else {
hoistedStatements = appendExportsOfHoistedDeclaration(hoistedStatements, node);
}
return undefined;
}
/**
* Visits a ClassDeclaration, hoisting its name to the outer module body function.
*
* @param node The node to visit.
*/
function visitClassDeclaration(node: ClassDeclaration): VisitResult<Statement> {
let statements: Statement[];
// Hoist the name of the class declaration to the outer module body function.
const name = getLocalName(node);
hoistVariableDeclaration(name);
// Rewrite the class declaration into an assignment of a class expression.
statements = append(statements,
setTextRange(
createStatement(
createAssignment(
name,
setTextRange(
createClassExpression(
/*modifiers*/ undefined,
node.name,
/*typeParameters*/ undefined,
visitNodes(node.heritageClauses, destructuringAndImportCallVisitor, isHeritageClause),
visitNodes(node.members, destructuringAndImportCallVisitor, isClassElement)
),
node
)
)
),
node
)
);
if (hasAssociatedEndOfDeclarationMarker(node)) {
// Defer exports until we encounter an EndOfDeclarationMarker node
const id = getOriginalNodeId(node);
deferredExports[id] = appendExportsOfHoistedDeclaration(deferredExports[id], node);
}
else {
statements = appendExportsOfHoistedDeclaration(statements, node);
}
return singleOrMany(statements);
}
/**
* Visits a variable statement, hoisting declared names to the top-level module body.
* Each declaration is rewritten into an assignment expression.
*
* @param node The node to visit.
*/
function visitVariableStatement(node: VariableStatement): VisitResult<Statement> {
if (!shouldHoistVariableDeclarationList(node.declarationList)) {
return visitNode(node, destructuringAndImportCallVisitor, isStatement);
}
let expressions: Expression[];
const isExportedDeclaration = hasModifier(node, ModifierFlags.Export);
const isMarkedDeclaration = hasAssociatedEndOfDeclarationMarker(node);
for (const variable of node.declarationList.declarations) {
if (variable.initializer) {
expressions = append(expressions, transformInitializedVariable(variable, isExportedDeclaration && !isMarkedDeclaration));
}
else {
hoistBindingElement(variable);
}
}
let statements: Statement[];
if (expressions) {
statements = append(statements, setTextRange(createStatement(inlineExpressions(expressions)), node));
}
if (isMarkedDeclaration) {
// Defer exports until we encounter an EndOfDeclarationMarker node
const id = getOriginalNodeId(node);
deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], node, isExportedDeclaration);
}
else {
statements = appendExportsOfVariableStatement(statements, node, /*exportSelf*/ false);
}
return singleOrMany(statements);
}
/**
* Hoists the declared names of a VariableDeclaration or BindingElement.
*
* @param node The declaration to hoist.
*/
function hoistBindingElement(node: VariableDeclaration | BindingElement): void {
if (isBindingPattern(node.name)) {
for (const element of node.name.elements) {
if (!isOmittedExpression(element)) {
hoistBindingElement(element);
}
}
}
else {
hoistVariableDeclaration(getSynthesizedClone(node.name));
}
}
/**
* Determines whether a VariableDeclarationList should be hoisted.
*
* @param node The node to test.
*/
function shouldHoistVariableDeclarationList(node: VariableDeclarationList) {
// hoist only non-block scoped declarations or block scoped declarations parented by source file
return (getEmitFlags(node) & EmitFlags.NoHoisting) === 0
&& (enclosingBlockScopedContainer.kind === SyntaxKind.SourceFile
|| (getOriginalNode(node).flags & NodeFlags.BlockScoped) === 0);
}
/**
* Transform an initialized variable declaration into an expression.
*
* @param node The node to transform.
* @param isExportedDeclaration A value indicating whether the variable is exported.
*/
function transformInitializedVariable(node: VariableDeclaration, isExportedDeclaration: boolean): Expression {
const createAssignment = isExportedDeclaration ? createExportedVariableAssignment : createNonExportedVariableAssignment;
return isBindingPattern(node.name)
? flattenDestructuringAssignment(
node,
destructuringAndImportCallVisitor,
context,
FlattenLevel.All,
/*needsValue*/ false,
createAssignment
)
: node.initializer ? createAssignment(node.name, visitNode(node.initializer, destructuringAndImportCallVisitor, isExpression)) : node.name;
}
/**
* Creates an assignment expression for an exported variable declaration.
*
* @param name The name of the variable.
* @param value The value of the variable's initializer.
* @param location The source map location for the assignment.
*/
function createExportedVariableAssignment(name: Identifier, value: Expression, location?: TextRange) {
return createVariableAssignment(name, value, location, /*isExportedDeclaration*/ true);
}
/**
* Creates an assignment expression for a non-exported variable declaration.
*
* @param name The name of the variable.
* @param value The value of the variable's initializer.
* @param location The source map location for the assignment.
*/
function createNonExportedVariableAssignment(name: Identifier, value: Expression, location?: TextRange) {
return createVariableAssignment(name, value, location, /*isExportedDeclaration*/ false);
}
/**
* Creates an assignment expression for a variable declaration.
*
* @param name The name of the variable.
* @param value The value of the variable's initializer.
* @param location The source map location for the assignment.
* @param isExportedDeclaration A value indicating whether the variable is exported.
*/
function createVariableAssignment(name: Identifier, value: Expression, location: TextRange, isExportedDeclaration: boolean) {
hoistVariableDeclaration(getSynthesizedClone(name));
return isExportedDeclaration
? createExportExpression(name, preventSubstitution(setTextRange(createAssignment(name, value), location)))
: preventSubstitution(setTextRange(createAssignment(name, value), location));
}
/**
* Visits a MergeDeclarationMarker used as a placeholder for the beginning of a merged
* and transformed declaration.
*
* @param node The node to visit.
*/
function visitMergeDeclarationMarker(node: MergeDeclarationMarker): VisitResult<Statement> {
// For an EnumDeclaration or ModuleDeclaration that merges with a preceeding
// declaration we do not emit a leading variable declaration. To preserve the
// begin/end semantics of the declararation and to properly handle exports
// we wrapped the leading variable declaration in a `MergeDeclarationMarker`.
//
// To balance the declaration, we defer the exports of the elided variable
// statement until we visit this declaration's `EndOfDeclarationMarker`.
if (hasAssociatedEndOfDeclarationMarker(node) && node.original.kind === SyntaxKind.VariableStatement) {
const id = getOriginalNodeId(node);
const isExportedDeclaration = hasModifier(node.original, ModifierFlags.Export);
deferredExports[id] = appendExportsOfVariableStatement(deferredExports[id], <VariableStatement>node.original, isExportedDeclaration);
}
return node;
}
/**
* Determines whether a node has an associated EndOfDeclarationMarker.
*
* @param node The node to test.
*/
function hasAssociatedEndOfDeclarationMarker(node: Node) {
return (getEmitFlags(node) & EmitFlags.HasEndOfDeclarationMarker) !== 0;
}
/**
* Visits a DeclarationMarker used as a placeholder for the end of a transformed
* declaration.
*
* @param node The node to visit.
*/
function visitEndOfDeclarationMarker(node: EndOfDeclarationMarker): VisitResult<Statement> {
// For some transformations we emit an `EndOfDeclarationMarker` to mark the actual
// end of the transformed declaration. We use this marker to emit any deferred exports
// of the declaration.
const id = getOriginalNodeId(node);
const statements = deferredExports[id];
if (statements) {
delete deferredExports[id];
return append(statements, node);
}
return node;
}
/**
* Appends the exports of an ImportDeclaration to a statement list, returning the
* statement list.
*
* @param statements A statement list to which the down-level export statements are to be
* appended. If `statements` is `undefined`, a new array is allocated if statements are
* appended.
* @param decl The declaration whose exports are to be recorded.
*/
function appendExportsOfImportDeclaration(statements: Statement[], decl: ImportDeclaration) {
if (moduleInfo.exportEquals) {
return statements;
}
const importClause = decl.importClause;
if (!importClause) {
return statements;
}
if (importClause.name) {
statements = appendExportsOfDeclaration(statements, importClause);
}
const namedBindings = importClause.namedBindings;
if (namedBindings) {
switch (namedBindings.kind) {
case SyntaxKind.NamespaceImport:
statements = appendExportsOfDeclaration(statements, namedBindings);
break;
case SyntaxKind.NamedImports:
for (const importBinding of namedBindings.elements) {
statements = appendExportsOfDeclaration(statements, importBinding);
}
break;
}
}
return statements;
}
/**
* Appends the export of an ImportEqualsDeclaration to a statement list, returning the
* statement list.
*
* @param statements A statement list to which the down-level export statements are to be
* appended. If `statements` is `undefined`, a new array is allocated if statements are
* appended.
* @param decl The declaration whose exports are to be recorded.
*/
function appendExportsOfImportEqualsDeclaration(statements: Statement[], decl: ImportEqualsDeclaration): Statement[] | undefined {
if (moduleInfo.exportEquals) {
return statements;
}
return appendExportsOfDeclaration(statements, decl);
}
/**
* Appends the exports of a VariableStatement to a statement list, returning the statement
* list.
*
* @param statements A statement list to which the down-level export statements are to be
* appended. If `statements` is `undefined`, a new array is allocated if statements are
* appended.
* @param node The VariableStatement whose exports are to be recorded.
* @param exportSelf A value indicating whether to also export each VariableDeclaration of
* `nodes` declaration list.
*/
function appendExportsOfVariableStatement(statements: Statement[] | undefined, node: VariableStatement, exportSelf: boolean): Statement[] | undefined {
if (moduleInfo.exportEquals) {
return statements;
}
for (const decl of node.declarationList.declarations) {
if (decl.initializer || exportSelf) {
statements = appendExportsOfBindingElement(statements, decl, exportSelf);
}
}
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