chore(cli-repl): clean autocomplete implementation up a bit

Best viewed as a whitespace-diff-disabled change, doesn't include
any functional work.

Author: addaleax

packages/cli-repl/src/mongosh-repl.ts

@@ -388,52 +388,59 @@ class MongoshNodeRepl implements EvaluationListener {
       null,
       instanceState.getAutocompleteParameters()
     );
-    (repl as Mutable<typeof repl>).completer = callbackify(
-      async (text: string): Promise<[string[], string]> => {
-        this.insideAutoCompleteOrGetPrompt = true;
-        try {
-          // Merge the results from the repl completer and the mongosh completer.
-          const [
-            [replResults, replOrig],
-            [mongoshResults, , mongoshResultsExclusive],
-          ] = await Promise.all([
-            (async () => (await origReplCompleter(text)) || [[]])(),
-            (async () => await mongoshCompleter(text))(),
-          ]);
-          this.bus.emit('mongosh:autocompletion-complete'); // For testing.
-
-          // Sometimes the mongosh completion knows that what it is doing is right,
-          // and that autocompletion based on inspecting the actual objects that
-          // are being accessed will not be helpful, e.g. in `use a<tab>`, we know
-          // that we want *only* database names and not e.g. `assert`.
-          if (mongoshResultsExclusive) {
-            return [mongoshResults, text];
-          }
+    const innerCompleter = async (
+      text: string
+    ): Promise<[string[], string]> => {
+      // Merge the results from the repl completer and the mongosh completer.
+      const [
+        [replResults, replOrig],
+        [mongoshResults, , mongoshResultsExclusive],
+      ] = await Promise.all([
+        (async () => (await origReplCompleter(text)) || [[]])(),
+        (async () => await mongoshCompleter(text))(),
+      ]);
+      this.bus.emit('mongosh:autocompletion-complete'); // For testing.
+
+      // Sometimes the mongosh completion knows that what it is doing is right,
+      // and that autocompletion based on inspecting the actual objects that
+      // are being accessed will not be helpful, e.g. in `use a<tab>`, we know
+      // that we want *only* database names and not e.g. `assert`.
+      if (mongoshResultsExclusive) {
+        return [mongoshResults, text];
+      }
 
-          // The REPL completer may not complete the entire string; for example,
-          // when completing ".ed" to ".editor", it reports as having completed
-          // only the last piece ("ed"), or when completing "{ $g", it completes
-          // only "$g" and not the entire result.
-          // The mongosh completer always completes on the entire string.
-          // In order to align them, we always extend the REPL results to include
-          // the full string prefix.
-          const replResultPrefix = replOrig
-            ? text.substr(0, text.lastIndexOf(replOrig))
-            : '';
-          const longReplResults = replResults.map(
-            (result: string) => replResultPrefix + result
-          );
+      // The REPL completer may not complete the entire string; for example,
+      // when completing ".ed" to ".editor", it reports as having completed
+      // only the last piece ("ed"), or when completing "{ $g", it completes
+      // only "$g" and not the entire result.
+      // The mongosh completer always completes on the entire string.
+      // In order to align them, we always extend the REPL results to include
+      // the full string prefix.
+      const replResultPrefix = replOrig
+        ? text.substr(0, text.lastIndexOf(replOrig))
+        : '';
+      const longReplResults = replResults.map(
+        (result: string) => replResultPrefix + result
+      );
+
+      // Remove duplicates, because shell API methods might otherwise show
+      // up in both completions.
+      const deduped = [...new Set([...longReplResults, ...mongoshResults])];
 
-          // Remove duplicates, because shell API methods might otherwise show
-          // up in both completions.
-          const deduped = [...new Set([...longReplResults, ...mongoshResults])];
+      return [deduped, text];
+    };
 
-          return [deduped, text];
+    const nodeReplCompleter = callbackify(
+      async (text: string): Promise<[string[], string]> => {
+        this.insideAutoCompleteOrGetPrompt = true;
+        try {
+          return await innerCompleter(text);
         } finally {
           this.insideAutoCompleteOrGetPrompt = false;
         }
       }
     );
+    (repl as Mutable<typeof repl>).completer = nodeReplCompleter;
 
     // This is used below for multiline history manipulation.
     let originalHistory: string[] | null = null;