parseTree() returns undefined on empty string input. Fixes #40

Author: aeschli

src/impl/parser.ts

@@ -209,7 +209,7 @@ export function parse(text: string, errors: ParseError[] = [], options: ParseOpt
 /**
  * Parses the given text and returns a tree representation the JSON content. On invalid input, the parser tries to be as fault tolerant as possible, but still return a result.
  */
-export function parseTree(text: string, errors: ParseError[] = [], options: ParseOptions = ParseOptions.DEFAULT): Node {
+export function parseTree(text: string, errors: ParseError[] = [], options: ParseOptions = ParseOptions.DEFAULT): Node | undefined {
 	let currentParent: NodeImpl = { type: 'array', offset: -1, length: -1, children: [], parent: undefined }; // artificial root
 
 	function ensurePropertyComplete(endOffset: number) {
@@ -276,7 +276,7 @@ export function parseTree(text: string, errors: ParseError[] = [], options: Pars
 /**
  * Finds the node at the given path in a JSON DOM.
  */
-export function findNodeAtLocation(root: Node, path: JSONPath): Node | undefined {
+export function findNodeAtLocation(root: Node | undefined, path: JSONPath): Node | undefined {
 	if (!root) {
 		return undefined;
 	}

src/main.ts

@@ -106,7 +106,7 @@ export const parse: (text: string, errors?: ParseError[], options?: ParseOptions
 /**
  * Parses the given text and returns a tree representation the JSON content. On invalid input, the parser tries to be as fault tolerant as possible, but still return a result.
  */
-export const parseTree: (text: string, errors?: ParseError[], options?: ParseOptions) => Node = parser.parseTree;
+export const parseTree: (text: string, errors?: ParseError[], options?: ParseOptions) => Node | undefined = parser.parseTree;
 
 /**
  * Finds the node at the given path in a JSON DOM.
@@ -167,7 +167,7 @@ export const enum ParseErrorCode {
 
 export function printParseErrorCode(code: ParseErrorCode) {
 	switch (code) {
-		case ParseErrorCode.InvalidSymbol: return 'InvalidSymbol';		case ParseErrorCode.InvalidNumberFormat: return 'InvalidNumberFormat';
+		case ParseErrorCode.InvalidSymbol: return 'InvalidSymbol'; case ParseErrorCode.InvalidNumberFormat: return 'InvalidNumberFormat';
 		case ParseErrorCode.PropertyNameExpected: return 'PropertyNameExpected';
 		case ParseErrorCode.ValueExpected: return 'ValueExpected';
 		case ParseErrorCode.ColonExpected: return 'ColonExpected';

src/test/json.test.ts

@@ -53,8 +53,8 @@ function assertTree(input: string, expected: any, expectedErrors: ParseError[] =
 	var actual = parseTree(input, errors);
 
 	assert.deepEqual(errors, expectedErrors);
-	let checkParent = (node: Node) => {
-		if (node.children) {
+	let checkParent = (node: Node | undefined) => {
+		if (node?.children) {
 			for (let child of node.children) {
 				assert.equal(node, child.parent);
 				delete (<any>child).parent; // delete to avoid recursion in deep equal
@@ -103,8 +103,8 @@ function assertVisit(input: string, expected: VisitorCallback[], expectedErrors:
 	assert.deepEqual(actuals, expected, JSON.stringify(actuals));
 }
 
-function assertNodeAtLocation(input: Node, segments: Segment[], expected: any) {
-	let actual = findNodeAtLocation(input, segments);
+function assertNodeAtLocation(input: Node | undefined, segments: Segment[], expected: any) {
+	let actual = input && findNodeAtLocation(input, segments);
 	assert.deepEqual(actual ? getNodeValue(actual) : void 0, expected);
 	if (actual) {
 		assert.deepEqual(getNodePath(actual), segments);