[TSVB] Fix more than one empty labels in markdown breaks the values f…

…or all other labels (elastic#100432) (elastic#100548)

* Fixed multiple empty labels monitoring with [].

* Fixed regexp group behavior and replaced by ''.replaceAll.

* Changed ''.replaceAll with ''.split(...).join(...)

* Added test for (empty) label case.

* Removed not necessary comment.

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

Co-authored-by: Kibana Machine <42973632+kibanamachine@users.noreply.github.com>

src/plugins/vis_type_timeseries/public/application/components/lib/replace_vars.js

@@ -14,7 +14,7 @@ import { i18n } from '@kbn/i18n';
 export function replaceVars(str, args = {}, vars = {}) {
   try {
     // we need add '[]' for emptyLabel because this value contains special characters. (https://handlebarsjs.com/guide/expressions.html#literal-segments)
-    const template = handlebars.compile(str.replace(emptyLabel, `[${emptyLabel}]`), {
+    const template = handlebars.compile(str.split(emptyLabel).join(`[${emptyLabel}]`), {
       strict: true,
       knownHelpersOnly: true,
     });

src/plugins/vis_type_timeseries/public/application/components/lib/replace_vars.test.js

@@ -7,6 +7,7 @@
  */
 
 import { replaceVars } from './replace_vars';
+import { emptyLabel } from '../../../../common/empty_label';
 
 describe('replaceVars(str, args, vars)', () => {
   test('replaces vars with values', () => {
@@ -27,4 +28,11 @@ describe('replaceVars(str, args, vars)', () => {
     const template = '# {{args.host}} {{total';
     expect(replaceVars(template, args, vars)).toEqual('# {{args.host}} {{total');
   });
+
+  test('replaces (empty).some_path with values', () => {
+    const vars = { [emptyLabel]: { d: { raw: 100 } } };
+    const args = {};
+    const template = `# {{ ${emptyLabel}.d.raw }} {{ ${emptyLabel}.d.raw }}`;
+    expect(replaceVars(template, args, vars)).toEqual('# 100 100');
+  });
 });