interface TypeWriterTypeResult {

line: number;

syntaxKind: number;

sourceText: string;

type: string;

}

interface TypeWriterSymbolResult {

line: number;

syntaxKind: number;

sourceText: string;

symbol: string;

}

interface TypeWriterResult {

line: number;

syntaxKind: number;

sourceText: string;

symbol?: string;

type?: string;

}

class TypeWriterWalker {

currentSourceFile: ts.SourceFile;

private checker: ts.TypeChecker;

constructor(private program: ts.Program, fullTypeCheck: boolean) {

// Consider getting both the diagnostics checker and the non-diagnostics checker to verify

// they are consistent.

this.checker = fullTypeCheck

? program.getDiagnosticsProducingTypeChecker()

: program.getTypeChecker();

}

public *getSymbols(fileName: string): IterableIterator<TypeWriterSymbolResult> {

const sourceFile = this.program.getSourceFile(fileName)!;

this.currentSourceFile = sourceFile;

const gen = this.visitNode(sourceFile, /*isSymbolWalk*/ true);

for (let {done, value} = gen.next(); !done; { done, value } = gen.next()) {

yield value as TypeWriterSymbolResult;

}

}

public *getTypes(fileName: string): IterableIterator<TypeWriterTypeResult> {

const sourceFile = this.program.getSourceFile(fileName)!;

this.currentSourceFile = sourceFile;

const gen = this.visitNode(sourceFile, /*isSymbolWalk*/ false);

for (let {done, value} = gen.next(); !done; { done, value } = gen.next()) {

yield value as TypeWriterTypeResult;

}

}

private *visitNode(node: ts.Node, isSymbolWalk: boolean): IterableIterator<TypeWriterResult> {

if (ts.isExpressionNode(node) || node.kind === ts.SyntaxKind.Identifier || ts.isDeclarationName(node)) {

const result = this.writeTypeOrSymbol(node, isSymbolWalk);

if (result) {

yield result;

}

}

const children: ts.Node[] = [];

ts.forEachChild(node, child => void children.push(child));

for (const child of children) {

const gen = this.visitNode(child, isSymbolWalk);

for (let {done, value} = gen.next(); !done; { done, value } = gen.next()) {

yield value;

}

}

}

private writeTypeOrSymbol(node: ts.Node, isSymbolWalk: boolean): TypeWriterResult | undefined {

const actualPos = ts.skipTrivia(this.currentSourceFile.text, node.pos);

const lineAndCharacter = this.currentSourceFile.getLineAndCharacterOfPosition(actualPos);

const sourceText = ts.getSourceTextOfNodeFromSourceFile(this.currentSourceFile, node);

if (!isSymbolWalk) {

// Don't try to get the type of something that's already a type.

// Exception for `T` in `type T = something` because that may evaluate to some interesting type.

if (ts.isPartOfTypeNode(node) || ts.isIdentifier(node) && !(ts.getMeaningFromDeclaration(node.parent) & ts.SemanticMeaning.Value) && !(ts.isTypeAlias(node.parent) && node.parent.name === node)) {

return undefined;

}

// Workaround to ensure we output 'C' instead of 'typeof C' for base class expressions

// let type = this.checker.getTypeAtLocation(node);

let type = ts.isExpressionWithTypeArgumentsInClassExtendsClause(node.parent) ? this.checker.getTypeAtLocation(node.parent) : undefined;

if (!type || type.flags & ts.TypeFlags.Any) type = this.checker.getTypeAtLocation(node);

const typeString = this.checker.typeToString(type, node.parent, ts.TypeFormatFlags.NoTruncation | ts.TypeFormatFlags.AllowUniqueESSymbolType);

return {

line: lineAndCharacter.line,

syntaxKind: node.kind,

sourceText,

type: typeString

};

}

const symbol = this.checker.getSymbolAtLocation(node);

if (!symbol) {

return;

}

let symbolString = "Symbol(" + this.checker.symbolToString(symbol, node.parent);

if (symbol.declarations) {

let count = 0;

for (const declaration of symbol.declarations) {

if (count >= 5) {

symbolString += ` ... and ${symbol.declarations.length - count} more`;

break;

}

count++;

symbolString += ", ";

if ((declaration as any).__symbolTestOutputCache) {

symbolString += (declaration as any).__symbolTestOutputCache;

continue;

}

const declSourceFile = declaration.getSourceFile();

const declLineAndCharacter = declSourceFile.getLineAndCharacterOfPosition(declaration.pos);

const fileName = ts.getBaseFileName(declSourceFile.fileName);

const isLibFile = /lib(.*)\.d\.ts/i.test(fileName);

const declText = `Decl(${ fileName }, ${ isLibFile ? "--" : declLineAndCharacter.line }, ${ isLibFile ? "--" : declLineAndCharacter.character })`;

symbolString += declText;

(declaration as any).__symbolTestOutputCache = declText;

}

}

symbolString += ")";

return {

line: lineAndCharacter.line,

syntaxKind: node.kind,

sourceText,

symbol: symbolString

};

}

}