src/services/breakpoints.ts

/* @internal */
namespace ts.BreakpointResolver {
    /**
     * Get the breakpoint span in given sourceFile
     */
    export function spanInSourceFileAtLocation(sourceFile: SourceFile, position: number) {
        // Cannot set breakpoint in dts file
        if (sourceFile.isDeclarationFile) {
            return undefined;
        }

        let tokenAtLocation = getTokenAtPosition(sourceFile, position);
        const lineOfPosition = sourceFile.getLineAndCharacterOfPosition(position).line;
        if (sourceFile.getLineAndCharacterOfPosition(tokenAtLocation.getStart(sourceFile)).line > lineOfPosition) {
            // Get previous token if the token is returned starts on new line
            // eg: let x =10; |--- cursor is here
            //     let y = 10;
            // token at position will return let keyword on second line as the token but we would like to use
            // token on same line if trailing trivia (comments or white spaces on same line) part of the last token on that line
            const preceding = findPrecedingToken(tokenAtLocation.pos, sourceFile);

            // It's a blank line
            if (!preceding || sourceFile.getLineAndCharacterOfPosition(preceding.getEnd()).line !== lineOfPosition) {
                return undefined;
            }
            tokenAtLocation = preceding;
        }

        // Cannot set breakpoint in ambient declarations
        if (tokenAtLocation.flags & NodeFlags.Ambient) {
            return undefined;
        }

        // Get the span in the node based on its syntax
        return spanInNode(tokenAtLocation);

        function textSpan(startNode: Node, endNode?: Node) {
            const lastDecorator = canHaveDecorators(startNode) ? findLast(startNode.modifiers, isDecorator) : undefined;
            const start = lastDecorator ?
                skipTrivia(sourceFile.text, lastDecorator.end) :
                startNode.getStart(sourceFile);
            return createTextSpanFromBounds(start, (endNode || startNode).getEnd());
        }

        function textSpanEndingAtNextToken(startNode: Node, previousTokenToFindNextEndToken: Node): TextSpan {
            return textSpan(startNode, findNextToken(previousTokenToFindNextEndToken, previousTokenToFindNextEndToken.parent, sourceFile));
        }

        function spanInNodeIfStartsOnSameLine(node: Node | undefined, otherwiseOnNode?: Node): TextSpan | undefined {
            if (node && lineOfPosition === sourceFile.getLineAndCharacterOfPosition(node.getStart(sourceFile)).line) {
                return spanInNode(node);
            }
            return spanInNode(otherwiseOnNode);
        }

        function spanInNodeArray<T extends Node>(nodeArray: NodeArray<T> | undefined, node: T, match: (value: Node) => boolean) {
            if (nodeArray) {
                const index = nodeArray.indexOf(node);
                if (index >= 0) {
                    let start = index;
                    let end = index + 1;
                    while (start > 0 && match(nodeArray[start - 1])) start--;
                    while (end < nodeArray.length && match(nodeArray[end])) end++;
                    return createTextSpanFromBounds(skipTrivia(sourceFile.text, nodeArray[start].pos), nodeArray[end - 1].end);
                }
            }
            return textSpan(node);
        }

        function spanInPreviousNode(node: Node): TextSpan | undefined {
            return spanInNode(findPrecedingToken(node.pos, sourceFile));
        }

        function spanInNextNode(node: Node): TextSpan | undefined {
            return spanInNode(findNextToken(node, node.parent, sourceFile));
        }

        function spanInNode(node: Node | undefined): TextSpan | undefined {
            if (node) {
                const { parent } = node;
                switch (node.kind) {
                    case SyntaxKind.VariableStatement:
                        // Span on first variable declaration
                        return spanInVariableDeclaration((node as VariableStatement).declarationList.declarations[0]);

                    case SyntaxKind.VariableDeclaration:
                    case SyntaxKind.PropertyDeclaration:
                    case SyntaxKind.PropertySignature:
                        return spanInVariableDeclaration(node as VariableDeclaration | PropertyDeclaration | PropertySignature);

                    case SyntaxKind.Parameter:
                        return spanInParameterDeclaration(node as ParameterDeclaration);

                    case SyntaxKind.FunctionDeclaration:
                    case SyntaxKind.MethodDeclaration:
                    case SyntaxKind.MethodSignature:
                    case SyntaxKind.GetAccessor:
                    case SyntaxKind.SetAccessor:
                    case SyntaxKind.Constructor:
                    case SyntaxKind.FunctionExpression:
                    case SyntaxKind.ArrowFunction:
                        return spanInFunctionDeclaration(node as FunctionLikeDeclaration);

                    case SyntaxKind.Block:
                        if (isFunctionBlock(node)) {
                            return spanInFunctionBlock(node as Block);
                        }
                        // falls through
                    case SyntaxKind.ModuleBlock:
                        return spanInBlock(node as Block);

                    case SyntaxKind.CatchClause:
                        return spanInBlock((node as CatchClause).block);

                    case SyntaxKind.ExpressionStatement:
                        // span on the expression
                        return textSpan((node as ExpressionStatement).expression);

                    case SyntaxKind.ReturnStatement:
                        // span on return keyword and expression if present
                        return textSpan(node.getChildAt(0), (node as ReturnStatement).expression);

                    case SyntaxKind.WhileStatement:
                        // Span on while(...)
                        return textSpanEndingAtNextToken(node, (node as WhileStatement).expression);

                    case SyntaxKind.DoStatement:
                        // span in statement of the do statement
                        return spanInNode((node as DoStatement).statement);

                    case SyntaxKind.DebuggerStatement:
                        // span on debugger keyword
                        return textSpan(node.getChildAt(0));

                    case SyntaxKind.IfStatement:
                        // set on if(..) span
                        return textSpanEndingAtNextToken(node, (node as IfStatement).expression);

                    case SyntaxKind.LabeledStatement:
                        // span in statement
                        return spanInNode((node as LabeledStatement).statement);

                    case SyntaxKind.BreakStatement:
                    case SyntaxKind.ContinueStatement:
                        // On break or continue keyword and label if present
                        return textSpan(node.getChildAt(0), (node as BreakOrContinueStatement).label);

                    case SyntaxKind.ForStatement:
                        return spanInForStatement(node as ForStatement);

                    case SyntaxKind.ForInStatement:
                        // span of for (a in ...)
                        return textSpanEndingAtNextToken(node, (node as ForInStatement).expression);

                    case SyntaxKind.ForOfStatement:
                        // span in initializer
                        return spanInInitializerOfForLike(node as ForOfStatement);

                    case SyntaxKind.SwitchStatement:
                        // span on switch(...)
                        return textSpanEndingAtNextToken(node, (node as SwitchStatement).expression);

                    case SyntaxKind.CaseClause:
                    case SyntaxKind.DefaultClause:
                        // span in first statement of the clause
                        return spanInNode((node as CaseOrDefaultClause).statements[0]);

                    case SyntaxKind.TryStatement:
                        // span in try block
                        return spanInBlock((node as TryStatement).tryBlock);

                    case SyntaxKind.ThrowStatement:
                        // span in throw ...
                        return textSpan(node, (node as ThrowStatement).expression);

                    case SyntaxKind.ExportAssignment:
                        // span on export = id
                        return textSpan(node, (node as ExportAssignment).expression);

                    case SyntaxKind.ImportEqualsDeclaration:
                        // import statement without including semicolon
                        return textSpan(node, (node as ImportEqualsDeclaration).moduleReference);

                    case SyntaxKind.ImportDeclaration:
                        // import statement without including semicolon
                        return textSpan(node, (node as ImportDeclaration).moduleSpecifier);

                    case SyntaxKind.ExportDeclaration:
                        // import statement without including semicolon
                        return textSpan(node, (node as ExportDeclaration).moduleSpecifier);

                    case SyntaxKind.ModuleDeclaration:
                        // span on complete module if it is instantiated
                        if (getModuleInstanceState(node as ModuleDeclaration) !== ModuleInstanceState.Instantiated) {
                            return undefined;
                        }
                        // falls through

                    case SyntaxKind.ClassDeclaration:
                    case SyntaxKind.EnumDeclaration:
                    case SyntaxKind.EnumMember:
                    case SyntaxKind.BindingElement:
                        // span on complete node
                        return textSpan(node);

                    case SyntaxKind.WithStatement:
                        // span in statement
                        return spanInNode((node as WithStatement).statement);

                    case SyntaxKind.Decorator:
                        return spanInNodeArray((parent as HasDecorators).modifiers, node, isDecorator);

                    case SyntaxKind.ObjectBindingPattern:
                    case SyntaxKind.ArrayBindingPattern:
                        return spanInBindingPattern(node as BindingPattern);

                    // No breakpoint in interface, type alias
                    case SyntaxKind.InterfaceDeclaration:
                    case SyntaxKind.TypeAliasDeclaration:
                        return undefined;

                    // Tokens:
                    case SyntaxKind.SemicolonToken:
                    case SyntaxKind.EndOfFileToken:
                        return spanInNodeIfStartsOnSameLine(findPrecedingToken(node.pos, sourceFile));

                    case SyntaxKind.CommaToken:
                        return spanInPreviousNode(node);

                    case SyntaxKind.OpenBraceToken:
                        return spanInOpenBraceToken(node);

                    case SyntaxKind.CloseBraceToken:
                        return spanInCloseBraceToken(node);

                    case SyntaxKind.CloseBracketToken:
                        return spanInCloseBracketToken(node);

                    case SyntaxKind.OpenParenToken:
                        return spanInOpenParenToken(node);

                    case SyntaxKind.CloseParenToken:
                        return spanInCloseParenToken(node);

                    case SyntaxKind.ColonToken:
                        return spanInColonToken(node);

                    case SyntaxKind.GreaterThanToken:
                    case SyntaxKind.LessThanToken:
                        return spanInGreaterThanOrLessThanToken(node);

                    // Keywords:
                    case SyntaxKind.WhileKeyword:
                        return spanInWhileKeyword(node);

                    case SyntaxKind.ElseKeyword:
                    case SyntaxKind.CatchKeyword:
                    case SyntaxKind.FinallyKeyword:
                        return spanInNextNode(node);

                    case SyntaxKind.OfKeyword:
                        return spanInOfKeyword(node);

                    default:
                        // Destructuring pattern in destructuring assignment
                        // [a, b, c] of
                        // [a, b, c] = expression
                        if (isArrayLiteralOrObjectLiteralDestructuringPattern(node)) {
                            return spanInArrayLiteralOrObjectLiteralDestructuringPattern(node as DestructuringPattern);
                        }

                        // Set breakpoint on identifier element of destructuring pattern
                        // `a` or `...c` or `d: x` from
                        // `[a, b, ...c]` or `{ a, b }` or `{ d: x }` from destructuring pattern
                        if ((node.kind === SyntaxKind.Identifier ||
                            node.kind === SyntaxKind.SpreadElement ||
                            node.kind === SyntaxKind.PropertyAssignment ||
                            node.kind === SyntaxKind.ShorthandPropertyAssignment) &&
                            isArrayLiteralOrObjectLiteralDestructuringPattern(parent)) {
                            return textSpan(node);
                        }

                        if (node.kind === SyntaxKind.BinaryExpression) {
                            const { left, operatorToken } = node as BinaryExpression;
                            // Set breakpoint in destructuring pattern if its destructuring assignment
                            // [a, b, c] or {a, b, c} of
                            // [a, b, c] = expression or
                            // {a, b, c} = expression
                            if (isArrayLiteralOrObjectLiteralDestructuringPattern(left)) {
                                return spanInArrayLiteralOrObjectLiteralDestructuringPattern(
                                    left as ArrayLiteralExpression | ObjectLiteralExpression);
                            }

                            if (operatorToken.kind === SyntaxKind.EqualsToken && isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
                                // Set breakpoint on assignment expression element of destructuring pattern
                                // a = expression of
                                // [a = expression, b, c] = someExpression or
                                // { a = expression, b, c } = someExpression
                                return textSpan(node);
                            }

                            if (operatorToken.kind === SyntaxKind.CommaToken) {
                                return spanInNode(left);
                            }
                        }

                        if (isExpressionNode(node)) {
                            switch (parent.kind) {
                                case SyntaxKind.DoStatement:
                                    // Set span as if on while keyword
                                    return spanInPreviousNode(node);

                                case SyntaxKind.Decorator:
                                    // Set breakpoint on the decorator emit
                                    return spanInNode(node.parent);

                                case SyntaxKind.ForStatement:
                                case SyntaxKind.ForOfStatement:
                                    return textSpan(node);

                                case SyntaxKind.BinaryExpression:
                                    if ((node.parent as BinaryExpression).operatorToken.kind === SyntaxKind.CommaToken) {
                                        // If this is a comma expression, the breakpoint is possible in this expression
                                        return textSpan(node);
                                    }
                                    break;

                                case SyntaxKind.ArrowFunction:
                                    if ((node.parent as FunctionLikeDeclaration).body === node) {
                                        // If this is body of arrow function, it is allowed to have the breakpoint
                                        return textSpan(node);
                                    }
                                    break;
                            }
                        }

                        switch (node.parent.kind) {
                            case SyntaxKind.PropertyAssignment:
                                // If this is name of property assignment, set breakpoint in the initializer
                                if ((node.parent as PropertyAssignment).name === node &&
                                    !isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent.parent)) {
                                    return spanInNode((node.parent as PropertyAssignment).initializer);
                                }
                                break;
                            case SyntaxKind.TypeAssertionExpression:
                                // Breakpoint in type assertion goes to its operand
                                if ((node.parent as TypeAssertion).type === node) {
                                    return spanInNextNode((node.parent as TypeAssertion).type);
                                }
                                break;
                            case SyntaxKind.VariableDeclaration:
                            case SyntaxKind.Parameter: {
                                // initializer of variable/parameter declaration go to previous node
                                const { initializer, type } = node.parent as VariableDeclaration | ParameterDeclaration;
                                if (initializer === node || type === node || isAssignmentOperator(node.kind)) {
                                    return spanInPreviousNode(node);
                                }
                                break;
                            }
                            case SyntaxKind.BinaryExpression: {
                                const { left } = node.parent as BinaryExpression;
                                if (isArrayLiteralOrObjectLiteralDestructuringPattern(left) && node !== left) {
                                    // If initializer of destructuring assignment move to previous token
                                    return spanInPreviousNode(node);
                                }
                                break;
                            }
                            default:
                                // return type of function go to previous token
                                if (isFunctionLike(node.parent) && node.parent.type === node) {
                                    return spanInPreviousNode(node);
                                }
                        }

                        // Default go to parent to set the breakpoint
                        return spanInNode(node.parent);
                }
            }

            function textSpanFromVariableDeclaration(variableDeclaration: VariableDeclaration | PropertyDeclaration | PropertySignature): TextSpan {
                if (isVariableDeclarationList(variableDeclaration.parent) && variableDeclaration.parent.declarations[0] === variableDeclaration) {
                    // First declaration - include let keyword
                    return textSpan(findPrecedingToken(variableDeclaration.pos, sourceFile, variableDeclaration.parent)!, variableDeclaration);
                }
                else {
                    // Span only on this declaration
                    return textSpan(variableDeclaration);
                }
            }

            function spanInVariableDeclaration(variableDeclaration: VariableDeclaration | PropertyDeclaration | PropertySignature): TextSpan | undefined {
                // If declaration of for in statement, just set the span in parent
                if (variableDeclaration.parent.parent.kind === SyntaxKind.ForInStatement) {
                    return spanInNode(variableDeclaration.parent.parent);
                }

                const parent = variableDeclaration.parent;
                // If this is a destructuring pattern, set breakpoint in binding pattern
                if (isBindingPattern(variableDeclaration.name)) {
                    return spanInBindingPattern(variableDeclaration.name);
                }

                // Breakpoint is possible in variableDeclaration only if there is initialization
                // or its declaration from 'for of'
                if ((hasOnlyExpressionInitializer(variableDeclaration) && variableDeclaration.initializer) ||
                    hasSyntacticModifier(variableDeclaration, ModifierFlags.Export) ||
                    parent.parent.kind === SyntaxKind.ForOfStatement) {
                    return textSpanFromVariableDeclaration(variableDeclaration);
                }

                if (isVariableDeclarationList(variableDeclaration.parent) &&
                    variableDeclaration.parent.declarations[0] !== variableDeclaration) {
                    // If we cannot set breakpoint on this declaration, set it on previous one
                    // Because the variable declaration may be binding pattern and
                    // we would like to set breakpoint in last binding element if that's the case,
                    // use preceding token instead
                    return spanInNode(findPrecedingToken(variableDeclaration.pos, sourceFile, variableDeclaration.parent));
                }
            }

            function canHaveSpanInParameterDeclaration(parameter: ParameterDeclaration): boolean {
                // Breakpoint is possible on parameter only if it has initializer, is a rest parameter, or has public or private modifier
                return !!parameter.initializer || parameter.dotDotDotToken !== undefined ||
                    hasSyntacticModifier(parameter, ModifierFlags.Public | ModifierFlags.Private);
            }

            function spanInParameterDeclaration(parameter: ParameterDeclaration): TextSpan | undefined {
                if (isBindingPattern(parameter.name)) {
                    // Set breakpoint in binding pattern
                    return spanInBindingPattern(parameter.name);
                }
                else if (canHaveSpanInParameterDeclaration(parameter)) {
                    return textSpan(parameter);
                }
                else {
                    const functionDeclaration = parameter.parent as FunctionLikeDeclaration;
                    const indexOfParameter = functionDeclaration.parameters.indexOf(parameter);
                    Debug.assert(indexOfParameter !== -1);
                    if (indexOfParameter !== 0) {
                        // Not a first parameter, go to previous parameter
                        return spanInParameterDeclaration(functionDeclaration.parameters[indexOfParameter - 1]);
                    }
                    else {
                        // Set breakpoint in the function declaration body
                        return spanInNode(functionDeclaration.body);
                    }
                }
            }

            function canFunctionHaveSpanInWholeDeclaration(functionDeclaration: FunctionLikeDeclaration) {
                return hasSyntacticModifier(functionDeclaration, ModifierFlags.Export) ||
                    (functionDeclaration.parent.kind === SyntaxKind.ClassDeclaration && functionDeclaration.kind !== SyntaxKind.Constructor);
            }

            function spanInFunctionDeclaration(functionDeclaration: FunctionLikeDeclaration): TextSpan | undefined {
                // No breakpoints in the function signature
                if (!functionDeclaration.body) {
                    return undefined;
                }

                if (canFunctionHaveSpanInWholeDeclaration(functionDeclaration)) {
                    // Set the span on whole function declaration
                    return textSpan(functionDeclaration);
                }

                // Set span in function body
                return spanInNode(functionDeclaration.body);
            }

            function spanInFunctionBlock(block: Block): TextSpan | undefined {
                const nodeForSpanInBlock = block.statements.length ? block.statements[0] : block.getLastToken();
                if (canFunctionHaveSpanInWholeDeclaration(block.parent as FunctionLikeDeclaration)) {
                    return spanInNodeIfStartsOnSameLine(block.parent, nodeForSpanInBlock);
                }

                return spanInNode(nodeForSpanInBlock);
            }

            function spanInBlock(block: Block): TextSpan | undefined {
                switch (block.parent.kind) {
                    case SyntaxKind.ModuleDeclaration:
                        if (getModuleInstanceState(block.parent as ModuleDeclaration) !== ModuleInstanceState.Instantiated) {
                            return undefined;
                        }

                    // Set on parent if on same line otherwise on first statement
                    // falls through
                    case SyntaxKind.WhileStatement:
                    case SyntaxKind.IfStatement:
                    case SyntaxKind.ForInStatement:
                        return spanInNodeIfStartsOnSameLine(block.parent, block.statements[0]);

                    // Set span on previous token if it starts on same line otherwise on the first statement of the block
                    case SyntaxKind.ForStatement:
                    case SyntaxKind.ForOfStatement:
                        return spanInNodeIfStartsOnSameLine(findPrecedingToken(block.pos, sourceFile, block.parent), block.statements[0]);
                }

                // Default action is to set on first statement
                return spanInNode(block.statements[0]);
            }

            function spanInInitializerOfForLike(forLikeStatement: ForStatement | ForOfStatement | ForInStatement): TextSpan | undefined {
                if (forLikeStatement.initializer!.kind === SyntaxKind.VariableDeclarationList) {
                    // Declaration list - set breakpoint in first declaration
                    const variableDeclarationList = forLikeStatement.initializer as VariableDeclarationList;
                    if (variableDeclarationList.declarations.length > 0) {
                        return spanInNode(variableDeclarationList.declarations[0]);
                    }
                }
                else {
                    // Expression - set breakpoint in it
                    return spanInNode(forLikeStatement.initializer);
                }
            }

            function spanInForStatement(forStatement: ForStatement): TextSpan | undefined {
                if (forStatement.initializer) {
                    return spanInInitializerOfForLike(forStatement);
                }

                if (forStatement.condition) {
                    return textSpan(forStatement.condition);
                }
                if (forStatement.incrementor) {
                    return textSpan(forStatement.incrementor);
                }
            }

            function spanInBindingPattern(bindingPattern: BindingPattern): TextSpan | undefined {
                // Set breakpoint in first binding element
                const firstBindingElement = forEach(bindingPattern.elements,
                    element => element.kind !== SyntaxKind.OmittedExpression ? element : undefined);

                if (firstBindingElement) {
                    return spanInNode(firstBindingElement);
                }

                // Empty binding pattern of binding element, set breakpoint on binding element
                if (bindingPattern.parent.kind === SyntaxKind.BindingElement) {
                    return textSpan(bindingPattern.parent);
                }

                // Variable declaration is used as the span
                return textSpanFromVariableDeclaration(bindingPattern.parent as VariableDeclaration);
            }

            function spanInArrayLiteralOrObjectLiteralDestructuringPattern(node: DestructuringPattern): TextSpan | undefined {
                Debug.assert(node.kind !== SyntaxKind.ArrayBindingPattern && node.kind !== SyntaxKind.ObjectBindingPattern);
                const elements: NodeArray<Expression | ObjectLiteralElement> = node.kind === SyntaxKind.ArrayLiteralExpression ? node.elements : node.properties;

                const firstBindingElement = forEach(elements,
                    element => element.kind !== SyntaxKind.OmittedExpression ? element : undefined);

                if (firstBindingElement) {
                    return spanInNode(firstBindingElement);
                }

                // Could be ArrayLiteral from destructuring assignment or
                // just nested element in another destructuring assignment
                // set breakpoint on assignment when parent is destructuring assignment
                // Otherwise set breakpoint for this element
                return textSpan(node.parent.kind === SyntaxKind.BinaryExpression ? node.parent : node);
            }

            // Tokens:
            function spanInOpenBraceToken(node: Node): TextSpan | undefined {
                switch (node.parent.kind) {
                    case SyntaxKind.EnumDeclaration:
                        const enumDeclaration = node.parent as EnumDeclaration;
                        return spanInNodeIfStartsOnSameLine(findPrecedingToken(node.pos, sourceFile, node.parent), enumDeclaration.members.length ? enumDeclaration.members[0] : enumDeclaration.getLastToken(sourceFile));

                    case SyntaxKind.ClassDeclaration:
                        const classDeclaration = node.parent as ClassDeclaration;
                        return spanInNodeIfStartsOnSameLine(findPrecedingToken(node.pos, sourceFile, node.parent), classDeclaration.members.length ? classDeclaration.members[0] : classDeclaration.getLastToken(sourceFile));

                    case SyntaxKind.CaseBlock:
                        return spanInNodeIfStartsOnSameLine(node.parent.parent, (node.parent as CaseBlock).clauses[0]);
                }

                // Default to parent node
                return spanInNode(node.parent);
            }

            function spanInCloseBraceToken(node: Node): TextSpan | undefined {
                switch (node.parent.kind) {
                    case SyntaxKind.ModuleBlock:
                        // If this is not an instantiated module block, no bp span
                        if (getModuleInstanceState(node.parent.parent as ModuleDeclaration) !== ModuleInstanceState.Instantiated) {
                            return undefined;
                        }
                        // falls through

                    case SyntaxKind.EnumDeclaration:
                    case SyntaxKind.ClassDeclaration:
                        // Span on close brace token
                        return textSpan(node);

                    case SyntaxKind.Block:
                        if (isFunctionBlock(node.parent)) {
                            // Span on close brace token
                            return textSpan(node);
                        }
                        // falls through

                    case SyntaxKind.CatchClause:
                        return spanInNode(lastOrUndefined((node.parent as Block).statements));

                    case SyntaxKind.CaseBlock:
                        // breakpoint in last statement of the last clause
                        const caseBlock = node.parent as CaseBlock;
                        const lastClause = lastOrUndefined(caseBlock.clauses);
                        if (lastClause) {
                            return spanInNode(lastOrUndefined(lastClause.statements));
                        }
                        return undefined;

                    case SyntaxKind.ObjectBindingPattern:
                        // Breakpoint in last binding element or binding pattern if it contains no elements
                        const bindingPattern = node.parent as BindingPattern;
                        return spanInNode(lastOrUndefined(bindingPattern.elements) || bindingPattern);

                    // Default to parent node
                    default:
                        if (isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
                            // Breakpoint in last binding element or binding pattern if it contains no elements
                            const objectLiteral = node.parent as ObjectLiteralExpression;
                            return textSpan(lastOrUndefined(objectLiteral.properties) || objectLiteral);
                        }
                        return spanInNode(node.parent);
                }
            }

            function spanInCloseBracketToken(node: Node): TextSpan | undefined {
                switch (node.parent.kind) {
                    case SyntaxKind.ArrayBindingPattern:
                        // Breakpoint in last binding element or binding pattern if it contains no elements
                        const bindingPattern = node.parent as BindingPattern;
                        return textSpan(lastOrUndefined(bindingPattern.elements) || bindingPattern);

                    default:
                        if (isArrayLiteralOrObjectLiteralDestructuringPattern(node.parent)) {
                            // Breakpoint in last binding element or binding pattern if it contains no elements
                            const arrayLiteral = node.parent as ArrayLiteralExpression;
                            return textSpan(lastOrUndefined(arrayLiteral.elements) || arrayLiteral);
                        }

                        // Default to parent node
                        return spanInNode(node.parent);
                }
            }

            function spanInOpenParenToken(node: Node): TextSpan | undefined {
                if (node.parent.kind === SyntaxKind.DoStatement || // Go to while keyword and do action instead
                    node.parent.kind === SyntaxKind.CallExpression ||
                    node.parent.kind === SyntaxKind.NewExpression) {
                    return spanInPreviousNode(node);
                }

                if (node.parent.kind === SyntaxKind.ParenthesizedExpression) {
                    return spanInNextNode(node);
                }

                // Default to parent node
                return spanInNode(node.parent);
            }

            function spanInCloseParenToken(node: Node): TextSpan | undefined {
                // Is this close paren token of parameter list, set span in previous token
                switch (node.parent.kind) {
                    case SyntaxKind.FunctionExpression:
                    case SyntaxKind.FunctionDeclaration:
                    case SyntaxKind.ArrowFunction:
                    case SyntaxKind.MethodDeclaration:
                    case SyntaxKind.MethodSignature:
                    case SyntaxKind.GetAccessor:
                    case SyntaxKind.SetAccessor:
                    case SyntaxKind.Constructor:
                    case SyntaxKind.WhileStatement:
                    case SyntaxKind.DoStatement:
                    case SyntaxKind.ForStatement:
                    case SyntaxKind.ForOfStatement:
                    case SyntaxKind.CallExpression:
                    case SyntaxKind.NewExpression:
                    case SyntaxKind.ParenthesizedExpression:
                        return spanInPreviousNode(node);

                    // Default to parent node
                    default:
                        return spanInNode(node.parent);
                }
            }

            function spanInColonToken(node: Node): TextSpan | undefined {
                // Is this : specifying return annotation of the function declaration
                if (isFunctionLike(node.parent) ||
                    node.parent.kind === SyntaxKind.PropertyAssignment ||
                    node.parent.kind === SyntaxKind.Parameter) {
                    return spanInPreviousNode(node);
                }

                return spanInNode(node.parent);
            }

            function spanInGreaterThanOrLessThanToken(node: Node): TextSpan | undefined {
                if (node.parent.kind === SyntaxKind.TypeAssertionExpression) {
                    return spanInNextNode(node);
                }

                return spanInNode(node.parent);
            }

            function spanInWhileKeyword(node: Node): TextSpan | undefined {
                if (node.parent.kind === SyntaxKind.DoStatement) {
                    // Set span on while expression
                    return textSpanEndingAtNextToken(node, (node.parent as DoStatement).expression);
                }

                // Default to parent node
                return spanInNode(node.parent);
            }

            function spanInOfKeyword(node: Node): TextSpan | undefined {
                if (node.parent.kind === SyntaxKind.ForOfStatement) {
                    // Set using next token
                    return spanInNextNode(node);
                }

                // Default to parent node
                return spanInNode(node.parent);
            }
        }
    }
}