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code-server/build/lib/treeshaking.ts

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/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the MIT License. See License.txt in the project root for license information.
*--------------------------------------------------------------------------------------------*/
'use strict';
import * as fs from 'fs';
import * as path from 'path';
import * as ts from 'typescript';
const TYPESCRIPT_LIB_FOLDER = path.dirname(require.resolve('typescript/lib/lib.d.ts'));
export const enum ShakeLevel {
Files = 0,
InnerFile = 1,
ClassMembers = 2
}
export function toStringShakeLevel(shakeLevel: ShakeLevel): string {
switch (shakeLevel) {
case ShakeLevel.Files:
return 'Files (0)';
case ShakeLevel.InnerFile:
return 'InnerFile (1)';
case ShakeLevel.ClassMembers:
return 'ClassMembers (2)';
}
}
export interface ITreeShakingOptions {
/**
* The full path to the root where sources are.
*/
sourcesRoot: string;
/**
* Module ids.
* e.g. `vs/editor/editor.main` or `index`
*/
entryPoints: string[];
/**
* Inline usages.
*/
inlineEntryPoints: string[];
/**
* Other .d.ts files
*/
typings: string[];
/**
* TypeScript compiler options.
*/
compilerOptions?: any;
/**
* The shake level to perform.
*/
shakeLevel: ShakeLevel;
/**
* regex pattern to ignore certain imports e.g. `vs/css!` imports
*/
importIgnorePattern: RegExp;
redirects: { [module: string]: string; };
}
export interface ITreeShakingResult {
[file: string]: string;
}
function printDiagnostics(options: ITreeShakingOptions, diagnostics: ReadonlyArray<ts.Diagnostic>): void {
for (const diag of diagnostics) {
let result = '';
if (diag.file) {
result += `${path.join(options.sourcesRoot, diag.file.fileName)}`;
}
if (diag.file && diag.start) {
let location = diag.file.getLineAndCharacterOfPosition(diag.start);
result += `:${location.line + 1}:${location.character}`;
}
result += ` - ` + JSON.stringify(diag.messageText);
console.log(result);
}
}
export function shake(options: ITreeShakingOptions): ITreeShakingResult {
const languageService = createTypeScriptLanguageService(options);
const program = languageService.getProgram()!;
const globalDiagnostics = program.getGlobalDiagnostics();
if (globalDiagnostics.length > 0) {
printDiagnostics(options, globalDiagnostics);
throw new Error(`Compilation Errors encountered.`);
}
const syntacticDiagnostics = program.getSyntacticDiagnostics();
if (syntacticDiagnostics.length > 0) {
printDiagnostics(options, syntacticDiagnostics);
throw new Error(`Compilation Errors encountered.`);
}
const semanticDiagnostics = program.getSemanticDiagnostics();
if (semanticDiagnostics.length > 0) {
printDiagnostics(options, semanticDiagnostics);
throw new Error(`Compilation Errors encountered.`);
}
markNodes(languageService, options);
return generateResult(languageService, options.shakeLevel);
}
//#region Discovery, LanguageService & Setup
function createTypeScriptLanguageService(options: ITreeShakingOptions): ts.LanguageService {
// Discover referenced files
const FILES = discoverAndReadFiles(options);
// Add fake usage files
options.inlineEntryPoints.forEach((inlineEntryPoint, index) => {
FILES[`inlineEntryPoint.${index}.ts`] = inlineEntryPoint;
});
// Add additional typings
options.typings.forEach((typing) => {
const filePath = path.join(options.sourcesRoot, typing);
FILES[typing] = fs.readFileSync(filePath).toString();
});
// Resolve libs
const RESOLVED_LIBS = processLibFiles(options);
const compilerOptions = ts.convertCompilerOptionsFromJson(options.compilerOptions, options.sourcesRoot).options;
const host = new TypeScriptLanguageServiceHost(RESOLVED_LIBS, FILES, compilerOptions);
return ts.createLanguageService(host);
}
/**
* Read imports and follow them until all files have been handled
*/
function discoverAndReadFiles(options: ITreeShakingOptions): IFileMap {
const FILES: IFileMap = {};
const in_queue: { [module: string]: boolean; } = Object.create(null);
const queue: string[] = [];
const enqueue = (moduleId: string) => {
if (in_queue[moduleId]) {
return;
}
in_queue[moduleId] = true;
queue.push(moduleId);
};
options.entryPoints.forEach((entryPoint) => enqueue(entryPoint));
while (queue.length > 0) {
const moduleId = queue.shift()!;
const dts_filename = path.join(options.sourcesRoot, moduleId + '.d.ts');
if (fs.existsSync(dts_filename)) {
const dts_filecontents = fs.readFileSync(dts_filename).toString();
FILES[`${moduleId}.d.ts`] = dts_filecontents;
continue;
}
const js_filename = path.join(options.sourcesRoot, moduleId + '.js');
if (fs.existsSync(js_filename)) {
// This is an import for a .js file, so ignore it...
continue;
}
let ts_filename: string;
if (options.redirects[moduleId]) {
ts_filename = path.join(options.sourcesRoot, options.redirects[moduleId] + '.ts');
} else {
ts_filename = path.join(options.sourcesRoot, moduleId + '.ts');
}
const ts_filecontents = fs.readFileSync(ts_filename).toString();
const info = ts.preProcessFile(ts_filecontents);
for (let i = info.importedFiles.length - 1; i >= 0; i--) {
const importedFileName = info.importedFiles[i].fileName;
if (options.importIgnorePattern.test(importedFileName)) {
// Ignore vs/css! imports
continue;
}
let importedModuleId = importedFileName;
if (/(^\.\/)|(^\.\.\/)/.test(importedModuleId)) {
importedModuleId = path.join(path.dirname(moduleId), importedModuleId);
}
enqueue(importedModuleId);
}
FILES[`${moduleId}.ts`] = ts_filecontents;
}
return FILES;
}
/**
* Read lib files and follow lib references
*/
function processLibFiles(options: ITreeShakingOptions): ILibMap {
const stack: string[] = [...options.compilerOptions.lib];
const result: ILibMap = {};
while (stack.length > 0) {
const filename = `lib.${stack.shift()!.toLowerCase()}.d.ts`;
const key = `defaultLib:${filename}`;
if (!result[key]) {
// add this file
const filepath = path.join(TYPESCRIPT_LIB_FOLDER, filename);
const sourceText = fs.readFileSync(filepath).toString();
result[key] = sourceText;
// precess dependencies and "recurse"
const info = ts.preProcessFile(sourceText);
for (let ref of info.libReferenceDirectives) {
stack.push(ref.fileName);
}
}
}
return result;
}
interface ILibMap { [libName: string]: string; }
interface IFileMap { [fileName: string]: string; }
/**
* A TypeScript language service host
*/
class TypeScriptLanguageServiceHost implements ts.LanguageServiceHost {
private readonly _libs: ILibMap;
private readonly _files: IFileMap;
private readonly _compilerOptions: ts.CompilerOptions;
constructor(libs: ILibMap, files: IFileMap, compilerOptions: ts.CompilerOptions) {
this._libs = libs;
this._files = files;
this._compilerOptions = compilerOptions;
}
// --- language service host ---------------
getCompilationSettings(): ts.CompilerOptions {
return this._compilerOptions;
}
getScriptFileNames(): string[] {
return (
([] as string[])
.concat(Object.keys(this._libs))
.concat(Object.keys(this._files))
);
}
getScriptVersion(_fileName: string): string {
return '1';
}
getProjectVersion(): string {
return '1';
}
getScriptSnapshot(fileName: string): ts.IScriptSnapshot {
if (this._files.hasOwnProperty(fileName)) {
return ts.ScriptSnapshot.fromString(this._files[fileName]);
} else if (this._libs.hasOwnProperty(fileName)) {
return ts.ScriptSnapshot.fromString(this._libs[fileName]);
} else {
return ts.ScriptSnapshot.fromString('');
}
}
getScriptKind(_fileName: string): ts.ScriptKind {
return ts.ScriptKind.TS;
}
getCurrentDirectory(): string {
return '';
}
getDefaultLibFileName(_options: ts.CompilerOptions): string {
return 'defaultLib:lib.d.ts';
}
isDefaultLibFileName(fileName: string): boolean {
return fileName === this.getDefaultLibFileName(this._compilerOptions);
}
}
//#endregion
//#region Tree Shaking
const enum NodeColor {
White = 0,
Gray = 1,
Black = 2
}
function getColor(node: ts.Node): NodeColor {
return (<any>node).$$$color || NodeColor.White;
}
function setColor(node: ts.Node, color: NodeColor): void {
(<any>node).$$$color = color;
}
function nodeOrParentIsBlack(node: ts.Node): boolean {
while (node) {
const color = getColor(node);
if (color === NodeColor.Black) {
return true;
}
node = node.parent;
}
return false;
}
function nodeOrChildIsBlack(node: ts.Node): boolean {
if (getColor(node) === NodeColor.Black) {
return true;
}
for (const child of node.getChildren()) {
if (nodeOrChildIsBlack(child)) {
return true;
}
}
return false;
}
function markNodes(languageService: ts.LanguageService, options: ITreeShakingOptions) {
const program = languageService.getProgram();
if (!program) {
throw new Error('Could not get program from language service');
}
if (options.shakeLevel === ShakeLevel.Files) {
// Mark all source files Black
program.getSourceFiles().forEach((sourceFile) => {
setColor(sourceFile, NodeColor.Black);
});
return;
}
const black_queue: ts.Node[] = [];
const gray_queue: ts.Node[] = [];
const export_import_queue: ts.Node[] = [];
const sourceFilesLoaded: { [fileName: string]: boolean } = {};
function enqueueTopLevelModuleStatements(sourceFile: ts.SourceFile): void {
sourceFile.forEachChild((node: ts.Node) => {
if (ts.isImportDeclaration(node)) {
if (!node.importClause && ts.isStringLiteral(node.moduleSpecifier)) {
setColor(node, NodeColor.Black);
enqueueImport(node, node.moduleSpecifier.text);
}
return;
}
if (ts.isExportDeclaration(node)) {
if (!node.exportClause && node.moduleSpecifier && ts.isStringLiteral(node.moduleSpecifier)) {
// export * from "foo";
setColor(node, NodeColor.Black);
enqueueImport(node, node.moduleSpecifier.text);
}
if (node.exportClause && ts.isNamedExports(node.exportClause)) {
for (const exportSpecifier of node.exportClause.elements) {
export_import_queue.push(exportSpecifier);
}
}
return;
}
if (
ts.isExpressionStatement(node)
|| ts.isIfStatement(node)
|| ts.isIterationStatement(node, true)
|| ts.isExportAssignment(node)
) {
enqueue_black(node);
}
if (ts.isImportEqualsDeclaration(node)) {
if (/export/.test(node.getFullText(sourceFile))) {
// e.g. "export import Severity = BaseSeverity;"
enqueue_black(node);
}
}
});
}
function enqueue_gray(node: ts.Node): void {
if (nodeOrParentIsBlack(node) || getColor(node) === NodeColor.Gray) {
return;
}
setColor(node, NodeColor.Gray);
gray_queue.push(node);
}
function enqueue_black(node: ts.Node): void {
const previousColor = getColor(node);
if (previousColor === NodeColor.Black) {
return;
}
if (previousColor === NodeColor.Gray) {
// remove from gray queue
gray_queue.splice(gray_queue.indexOf(node), 1);
setColor(node, NodeColor.White);
// add to black queue
enqueue_black(node);
// // move from one queue to the other
// black_queue.push(node);
// setColor(node, NodeColor.Black);
return;
}
if (nodeOrParentIsBlack(node)) {
return;
}
const fileName = node.getSourceFile().fileName;
if (/^defaultLib:/.test(fileName) || /\.d\.ts$/.test(fileName)) {
setColor(node, NodeColor.Black);
return;
}
const sourceFile = node.getSourceFile();
if (!sourceFilesLoaded[sourceFile.fileName]) {
sourceFilesLoaded[sourceFile.fileName] = true;
enqueueTopLevelModuleStatements(sourceFile);
}
if (ts.isSourceFile(node)) {
return;
}
setColor(node, NodeColor.Black);
black_queue.push(node);
if (options.shakeLevel === ShakeLevel.ClassMembers && (ts.isMethodDeclaration(node) || ts.isMethodSignature(node) || ts.isPropertySignature(node) || ts.isPropertyDeclaration(node) || ts.isGetAccessor(node) || ts.isSetAccessor(node))) {
const references = languageService.getReferencesAtPosition(node.getSourceFile().fileName, node.name.pos + node.name.getLeadingTriviaWidth());
if (references) {
for (let i = 0, len = references.length; i < len; i++) {
const reference = references[i];
const referenceSourceFile = program!.getSourceFile(reference.fileName);
if (!referenceSourceFile) {
continue;
}
const referenceNode = getTokenAtPosition(referenceSourceFile, reference.textSpan.start, false, false);
if (
ts.isMethodDeclaration(referenceNode.parent)
|| ts.isPropertyDeclaration(referenceNode.parent)
|| ts.isGetAccessor(referenceNode.parent)
|| ts.isSetAccessor(referenceNode.parent)
) {
enqueue_gray(referenceNode.parent);
}
}
}
}
}
function enqueueFile(filename: string): void {
const sourceFile = program!.getSourceFile(filename);
if (!sourceFile) {
console.warn(`Cannot find source file ${filename}`);
return;
}
enqueue_black(sourceFile);
}
function enqueueImport(node: ts.Node, importText: string): void {
if (options.importIgnorePattern.test(importText)) {
// this import should be ignored
return;
}
const nodeSourceFile = node.getSourceFile();
let fullPath: string;
if (/(^\.\/)|(^\.\.\/)/.test(importText)) {
fullPath = path.join(path.dirname(nodeSourceFile.fileName), importText) + '.ts';
} else {
fullPath = importText + '.ts';
}
enqueueFile(fullPath);
}
options.entryPoints.forEach(moduleId => enqueueFile(moduleId + '.ts'));
// Add fake usage files
options.inlineEntryPoints.forEach((_, index) => enqueueFile(`inlineEntryPoint.${index}.ts`));
let step = 0;
const checker = program.getTypeChecker();
while (black_queue.length > 0 || gray_queue.length > 0) {
++step;
let node: ts.Node;
if (step % 100 === 0) {
console.log(`Treeshaking - ${Math.floor(100 * step / (step + black_queue.length + gray_queue.length))}% - ${step}/${step + black_queue.length + gray_queue.length} (${black_queue.length}, ${gray_queue.length})`);
}
if (black_queue.length === 0) {
for (let i = 0; i < gray_queue.length; i++) {
const node = gray_queue[i];
const nodeParent = node.parent;
if ((ts.isClassDeclaration(nodeParent) || ts.isInterfaceDeclaration(nodeParent)) && nodeOrChildIsBlack(nodeParent)) {
gray_queue.splice(i, 1);
black_queue.push(node);
setColor(node, NodeColor.Black);
i--;
}
}
}
if (black_queue.length > 0) {
node = black_queue.shift()!;
} else {
// only gray nodes remaining...
break;
}
const nodeSourceFile = node.getSourceFile();
const loop = (node: ts.Node) => {
const [symbol, symbolImportNode] = getRealNodeSymbol(checker, node);
if (symbolImportNode) {
setColor(symbolImportNode, NodeColor.Black);
}
if (symbol && !nodeIsInItsOwnDeclaration(nodeSourceFile, node, symbol)) {
for (let i = 0, len = symbol.declarations.length; i < len; i++) {
const declaration = symbol.declarations[i];
if (ts.isSourceFile(declaration)) {
// Do not enqueue full source files
// (they can be the declaration of a module import)
continue;
}
if (options.shakeLevel === ShakeLevel.ClassMembers && (ts.isClassDeclaration(declaration) || ts.isInterfaceDeclaration(declaration)) && !isLocalCodeExtendingOrInheritingFromDefaultLibSymbol(program, checker, declaration)) {
enqueue_black(declaration.name!);
for (let j = 0; j < declaration.members.length; j++) {
const member = declaration.members[j];
const memberName = member.name ? member.name.getText() : null;
if (
ts.isConstructorDeclaration(member)
|| ts.isConstructSignatureDeclaration(member)
|| ts.isIndexSignatureDeclaration(member)
|| ts.isCallSignatureDeclaration(member)
|| memberName === '[Symbol.iterator]'
|| memberName === '[Symbol.toStringTag]'
|| memberName === 'toJSON'
|| memberName === 'toString'
|| memberName === 'dispose'// TODO: keeping all `dispose` methods
|| /^_(.*)Brand$/.test(memberName || '') // TODO: keeping all members ending with `Brand`...
) {
enqueue_black(member);
}
}
// queue the heritage clauses
if (declaration.heritageClauses) {
for (let heritageClause of declaration.heritageClauses) {
enqueue_black(heritageClause);
}
}
} else {
enqueue_black(declaration);
}
}
}
node.forEachChild(loop);
};
node.forEachChild(loop);
}
while (export_import_queue.length > 0) {
const node = export_import_queue.shift()!;
if (nodeOrParentIsBlack(node)) {
continue;
}
const symbol: ts.Symbol | undefined = (<any>node).symbol;
if (!symbol) {
continue;
}
const aliased = checker.getAliasedSymbol(symbol);
if (aliased.declarations && aliased.declarations.length > 0) {
if (nodeOrParentIsBlack(aliased.declarations[0]) || nodeOrChildIsBlack(aliased.declarations[0])) {
setColor(node, NodeColor.Black);
}
}
}
}
function nodeIsInItsOwnDeclaration(nodeSourceFile: ts.SourceFile, node: ts.Node, symbol: ts.Symbol): boolean {
for (let i = 0, len = symbol.declarations.length; i < len; i++) {
const declaration = symbol.declarations[i];
const declarationSourceFile = declaration.getSourceFile();
if (nodeSourceFile === declarationSourceFile) {
if (declaration.pos <= node.pos && node.end <= declaration.end) {
return true;
}
}
}
return false;
}
function generateResult(languageService: ts.LanguageService, shakeLevel: ShakeLevel): ITreeShakingResult {
const program = languageService.getProgram();
if (!program) {
throw new Error('Could not get program from language service');
}
let result: ITreeShakingResult = {};
const writeFile = (filePath: string, contents: string): void => {
result[filePath] = contents;
};
program.getSourceFiles().forEach((sourceFile) => {
const fileName = sourceFile.fileName;
if (/^defaultLib:/.test(fileName)) {
return;
}
const destination = fileName;
if (/\.d\.ts$/.test(fileName)) {
if (nodeOrChildIsBlack(sourceFile)) {
writeFile(destination, sourceFile.text);
}
return;
}
let text = sourceFile.text;
let result = '';
function keep(node: ts.Node): void {
result += text.substring(node.pos, node.end);
}
function write(data: string): void {
result += data;
}
function writeMarkedNodes(node: ts.Node): void {
if (getColor(node) === NodeColor.Black) {
return keep(node);
}
// Always keep certain top-level statements
if (ts.isSourceFile(node.parent)) {
if (ts.isExpressionStatement(node) && ts.isStringLiteral(node.expression) && node.expression.text === 'use strict') {
return keep(node);
}
if (ts.isVariableStatement(node) && nodeOrChildIsBlack(node)) {
return keep(node);
}
}
// Keep the entire import in import * as X cases
if (ts.isImportDeclaration(node)) {
if (node.importClause && node.importClause.namedBindings) {
if (ts.isNamespaceImport(node.importClause.namedBindings)) {
if (getColor(node.importClause.namedBindings) === NodeColor.Black) {
return keep(node);
}
} else {
let survivingImports: string[] = [];
for (const importNode of node.importClause.namedBindings.elements) {
if (getColor(importNode) === NodeColor.Black) {
survivingImports.push(importNode.getFullText(sourceFile));
}
}
const leadingTriviaWidth = node.getLeadingTriviaWidth();
const leadingTrivia = sourceFile.text.substr(node.pos, leadingTriviaWidth);
if (survivingImports.length > 0) {
if (node.importClause && node.importClause.name && getColor(node.importClause) === NodeColor.Black) {
return write(`${leadingTrivia}import ${node.importClause.name.text}, {${survivingImports.join(',')} } from${node.moduleSpecifier.getFullText(sourceFile)};`);
}
return write(`${leadingTrivia}import {${survivingImports.join(',')} } from${node.moduleSpecifier.getFullText(sourceFile)};`);
} else {
if (node.importClause && node.importClause.name && getColor(node.importClause) === NodeColor.Black) {
return write(`${leadingTrivia}import ${node.importClause.name.text} from${node.moduleSpecifier.getFullText(sourceFile)};`);
}
}
}
} else {
if (node.importClause && getColor(node.importClause) === NodeColor.Black) {
return keep(node);
}
}
}
if (ts.isExportDeclaration(node)) {
if (node.exportClause && node.moduleSpecifier && ts.isNamedExports(node.exportClause)) {
let survivingExports: string[] = [];
for (const exportSpecifier of node.exportClause.elements) {
if (getColor(exportSpecifier) === NodeColor.Black) {
survivingExports.push(exportSpecifier.getFullText(sourceFile));
}
}
const leadingTriviaWidth = node.getLeadingTriviaWidth();
const leadingTrivia = sourceFile.text.substr(node.pos, leadingTriviaWidth);
if (survivingExports.length > 0) {
return write(`${leadingTrivia}export {${survivingExports.join(',')} } from${node.moduleSpecifier.getFullText(sourceFile)};`);
}
}
}
if (shakeLevel === ShakeLevel.ClassMembers && (ts.isClassDeclaration(node) || ts.isInterfaceDeclaration(node)) && nodeOrChildIsBlack(node)) {
let toWrite = node.getFullText();
for (let i = node.members.length - 1; i >= 0; i--) {
const member = node.members[i];
if (getColor(member) === NodeColor.Black || !member.name) {
// keep method
continue;
}
let pos = member.pos - node.pos;
let end = member.end - node.pos;
toWrite = toWrite.substring(0, pos) + toWrite.substring(end);
}
return write(toWrite);
}
if (ts.isFunctionDeclaration(node)) {
// Do not go inside functions if they haven't been marked
return;
}
node.forEachChild(writeMarkedNodes);
}
if (getColor(sourceFile) !== NodeColor.Black) {
if (!nodeOrChildIsBlack(sourceFile)) {
// none of the elements are reachable => don't write this file at all!
return;
}
sourceFile.forEachChild(writeMarkedNodes);
result += sourceFile.endOfFileToken.getFullText(sourceFile);
} else {
result = text;
}
writeFile(destination, result);
});
return result;
}
//#endregion
//#region Utils
function isLocalCodeExtendingOrInheritingFromDefaultLibSymbol(program: ts.Program, checker: ts.TypeChecker, declaration: ts.ClassDeclaration | ts.InterfaceDeclaration): boolean {
if (!program.isSourceFileDefaultLibrary(declaration.getSourceFile()) && declaration.heritageClauses) {
for (const heritageClause of declaration.heritageClauses) {
for (const type of heritageClause.types) {
const symbol = findSymbolFromHeritageType(checker, type);
if (symbol) {
const decl = symbol.valueDeclaration || (symbol.declarations && symbol.declarations[0]);
if (decl && program.isSourceFileDefaultLibrary(decl.getSourceFile())) {
return true;
}
}
}
}
}
return false;
}
function findSymbolFromHeritageType(checker: ts.TypeChecker, type: ts.ExpressionWithTypeArguments | ts.Expression | ts.PrivateIdentifier): ts.Symbol | null {
if (ts.isExpressionWithTypeArguments(type)) {
return findSymbolFromHeritageType(checker, type.expression);
}
if (ts.isIdentifier(type)) {
return getRealNodeSymbol(checker, type)[0];
}
if (ts.isPropertyAccessExpression(type)) {
return findSymbolFromHeritageType(checker, type.name);
}
return null;
}
/**
* Returns the node's symbol and the `import` node (if the symbol resolved from a different module)
*/
function getRealNodeSymbol(checker: ts.TypeChecker, node: ts.Node): [ts.Symbol | null, ts.Declaration | null] {
// Use some TypeScript internals to avoid code duplication
type ObjectLiteralElementWithName = ts.ObjectLiteralElement & { name: ts.PropertyName; parent: ts.ObjectLiteralExpression | ts.JsxAttributes };
const getPropertySymbolsFromContextualType: (node: ObjectLiteralElementWithName, checker: ts.TypeChecker, contextualType: ts.Type, unionSymbolOk: boolean) => ReadonlyArray<ts.Symbol> = (<any>ts).getPropertySymbolsFromContextualType;
const getContainingObjectLiteralElement: (node: ts.Node) => ObjectLiteralElementWithName | undefined = (<any>ts).getContainingObjectLiteralElement;
const getNameFromPropertyName: (name: ts.PropertyName) => string | undefined = (<any>ts).getNameFromPropertyName;
// Go to the original declaration for cases:
//
// (1) when the aliased symbol was declared in the location(parent).
// (2) when the aliased symbol is originating from an import.
//
function shouldSkipAlias(node: ts.Node, declaration: ts.Node): boolean {
if (!ts.isShorthandPropertyAssignment(node) && node.kind !== ts.SyntaxKind.Identifier) {
return false;
}
if (node.parent === declaration) {
return true;
}
switch (declaration.kind) {
case ts.SyntaxKind.ImportClause:
case ts.SyntaxKind.ImportEqualsDeclaration:
return true;
case ts.SyntaxKind.ImportSpecifier:
return declaration.parent.kind === ts.SyntaxKind.NamedImports;
default:
return false;
}
}
if (!ts.isShorthandPropertyAssignment(node)) {
if (node.getChildCount() !== 0) {
return [null, null];
}
}
const { parent } = node;
let symbol = (
ts.isShorthandPropertyAssignment(node)
? checker.getShorthandAssignmentValueSymbol(node)
: checker.getSymbolAtLocation(node)
);
let importNode: ts.Declaration | null = null;
// If this is an alias, and the request came at the declaration location
// get the aliased symbol instead. This allows for goto def on an import e.g.
// import {A, B} from "mod";
// to jump to the implementation directly.
if (symbol && symbol.flags & ts.SymbolFlags.Alias && shouldSkipAlias(node, symbol.declarations[0])) {
const aliased = checker.getAliasedSymbol(symbol);
if (aliased.declarations) {
// We should mark the import as visited
importNode = symbol.declarations[0];
symbol = aliased;
}
}
if (symbol) {
// Because name in short-hand property assignment has two different meanings: property name and property value,
// using go-to-definition at such position should go to the variable declaration of the property value rather than
// go to the declaration of the property name (in this case stay at the same position). However, if go-to-definition
// is performed at the location of property access, we would like to go to definition of the property in the short-hand
// assignment. This case and others are handled by the following code.
if (node.parent.kind === ts.SyntaxKind.ShorthandPropertyAssignment) {
symbol = checker.getShorthandAssignmentValueSymbol(symbol.valueDeclaration);
}
// If the node is the name of a BindingElement within an ObjectBindingPattern instead of just returning the
// declaration the symbol (which is itself), we should try to get to the original type of the ObjectBindingPattern
// and return the property declaration for the referenced property.
// For example:
// import('./foo').then(({ b/*goto*/ar }) => undefined); => should get use to the declaration in file "./foo"
//
// function bar<T>(onfulfilled: (value: T) => void) { //....}
// interface Test {
// pr/*destination*/op1: number
// }
// bar<Test>(({pr/*goto*/op1})=>{});
if (ts.isPropertyName(node) && ts.isBindingElement(parent) && ts.isObjectBindingPattern(parent.parent) &&
(node === (parent.propertyName || parent.name))) {
const name = getNameFromPropertyName(node);
const type = checker.getTypeAtLocation(parent.parent);
if (name && type) {
if (type.isUnion()) {
const prop = type.types[0].getProperty(name);
if (prop) {
symbol = prop;
}
} else {
const prop = type.getProperty(name);
if (prop) {
symbol = prop;
}
}
}
}
// If the current location we want to find its definition is in an object literal, try to get the contextual type for the
// object literal, lookup the property symbol in the contextual type, and use this for goto-definition.
// For example
// interface Props{
// /*first*/prop1: number
// prop2: boolean
// }
// function Foo(arg: Props) {}
// Foo( { pr/*1*/op1: 10, prop2: false })
const element = getContainingObjectLiteralElement(node);
if (element) {
const contextualType = element && checker.getContextualType(element.parent);
if (contextualType) {
const propertySymbols = getPropertySymbolsFromContextualType(element, checker, contextualType, /*unionSymbolOk*/ false);
if (propertySymbols) {
symbol = propertySymbols[0];
}
}
}
}
if (symbol && symbol.declarations) {
return [symbol, importNode];
}
return [null, null];
}
/** Get the token whose text contains the position */
function getTokenAtPosition(sourceFile: ts.SourceFile, position: number, allowPositionInLeadingTrivia: boolean, includeEndPosition: boolean): ts.Node {
let current: ts.Node = sourceFile;
outer: while (true) {
// find the child that contains 'position'
for (const child of current.getChildren()) {
const start = allowPositionInLeadingTrivia ? child.getFullStart() : child.getStart(sourceFile, /*includeJsDoc*/ true);
if (start > position) {
// If this child begins after position, then all subsequent children will as well.
break;
}
const end = child.getEnd();
if (position < end || (position === end && (child.kind === ts.SyntaxKind.EndOfFileToken || includeEndPosition))) {
current = child;
continue outer;
}
}
return current;
}
}
//#endregion