feat(output-parsers): add empty check

Author: ItzCrazyKns

src/lib/outputParsers/lineOutputParser.ts

@@ -19,6 +19,8 @@ class LineOutputParser extends BaseOutputParser<string> {
   lc_namespace = ['langchain', 'output_parsers', 'line_output_parser'];
 
   async parse(text: string): Promise<string> {
+    text = text.trim() || '';
+
     const regex = /^(\s*(-|\*|\d+\.\s|\d+\)\s|\u2022)\s*)+/;
     const startKeyIndex = text.indexOf(`<${this.key}>`);
     const endKeyIndex = text.indexOf(`</${this.key}>`);

src/lib/outputParsers/listLineOutputParser.ts

@@ -19,11 +19,13 @@ class LineListOutputParser extends BaseOutputParser<string[]> {
   lc_namespace = ['langchain', 'output_parsers', 'line_list_output_parser'];
 
   async parse(text: string): Promise<string[]> {
+    text = text.trim() || '';
+
     const regex = /^(\s*(-|\*|\d+\.\s|\d+\)\s|\u2022)\s*)+/;
     const startKeyIndex = text.indexOf(`<${this.key}>`);
     const endKeyIndex = text.indexOf(`</${this.key}>`);
 
-    if (startKeyIndex === -1 && endKeyIndex === -1) {
+    if (startKeyIndex === -1 || endKeyIndex === -1) {
       return [];
     }