fixup: restructure, add comments

Author: addaleax

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

@@ -5,7 +5,7 @@ import type { ReadLineOptions } from 'readline';
 import type { ReplOptions, REPLServer } from 'repl';
 import type { start as originalStart } from 'repl';
 import { promisify } from 'util';
-import type { KeypressKey } from './repl-paste-support';
+import { prototypeChain, type KeypressKey } from './repl-paste-support';
 
 // Utility, inverse of Readonly<T>
 type Mutable<T> = {
@@ -407,3 +407,39 @@ function wrapPauseInput<Args extends any[], Ret>(
     }
   };
 }
+
+// Not related to paste support, but rather for integrating with the MongoshNodeRepl's
+// line-by-line input handling. Calling this methods adds hooks to `repl` that are called
+// when the REPL is ready to evaluate further input. Eventually, like the other code
+// in this file, we should upstream this into Node.js core and/or evaluate the need for
+// it entirely.
+export function addReplEventForEvalReady(
+  repl: REPLServer,
+  before: () => boolean,
+  after: () => void
+): void {
+  const wrapMethodWithLineByLineInputNextLine = (
+    repl: REPLServer,
+    key: keyof REPLServer
+  ) => {
+    if (!repl[key]) return;
+    const originalMethod = repl[key].bind(repl);
+    (repl as any)[key] = (...args: any[]) => {
+      if (!before()) {
+        return;
+      }
+      const result = originalMethod(...args);
+      after();
+      return result;
+    };
+  };
+  // https://github.com/nodejs/node/blob/88f4cef8b96b2bb9d4a92f6848ce4d63a82879a8/lib/internal/readline/interface.js#L954
+  // added in https://github.com/nodejs/node/commit/96be7836d794509dd455e66d91c2975419feed64
+  // handles newlines inside multi-line input and replaces `.displayPrompt()` which was
+  // previously used to print the prompt for multi-line input.
+  const addNewLineOnTTYKey = [...prototypeChain(repl)]
+    .flatMap((proto) => Object.getOwnPropertySymbols(proto))
+    .find((s) => String(s).includes('(_addNewLineOnTTY)')) as keyof REPLServer;
+  wrapMethodWithLineByLineInputNextLine(repl, 'displayPrompt');
+  wrapMethodWithLineByLineInputNextLine(repl, addNewLineOnTTYKey);
+}

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

@@ -47,10 +47,7 @@ import type { FormatOptions } from './format-output';
 import { markTime } from './startup-timing';
 import type { Context } from 'vm';
 import { Script, createContext, runInContext } from 'vm';
-import {
-  addReplEventForEvalReady,
-  installPasteSupport,
-} from './repl-paste-support';
+import { installPasteSupport } from './repl-paste-support';
 import util from 'util';
 
 declare const __non_webpack_require__: any;
@@ -524,7 +521,7 @@ class MongoshNodeRepl implements EvaluationListener {
     // This is used below for multiline history manipulation.
     let originalHistory: string[] | null = null;
 
-    addReplEventForEvalReady(
+    asyncRepl.addReplEventForEvalReady(
       repl,
       () => !!this.started,
       () => this.lineByLineInput.nextLine()

packages/cli-repl/src/repl-paste-support.ts

@@ -11,7 +11,7 @@ export type KeypressKey = {
   code?: string;
 };
 
-function* prototypeChain(obj: unknown): Iterable<unknown> {
+export function* prototypeChain(obj: unknown): Iterable<unknown> {
   if (!obj) return;
   yield obj;
   yield* prototypeChain(Object.getPrototypeOf(obj));
@@ -65,36 +65,3 @@ export function installPasteSupport(repl: REPLServer): string {
   });
   return onEnd;
 }
-
-// Not related to paste support, but rather for integrating with the MongoshNodeRepl's
-// line-by-line input handling.
-export function addReplEventForEvalReady(
-  repl: REPLServer,
-  before: () => boolean,
-  after: () => void
-): void {
-  const wrapMethodWithLineByLineInputNextLine = (
-    repl: REPLServer,
-    key: keyof REPLServer
-  ) => {
-    if (!repl[key]) return;
-    const originalMethod = repl[key].bind(repl);
-    (repl as any)[key] = (...args: any[]) => {
-      if (!before()) {
-        return;
-      }
-      const result = originalMethod(...args);
-      after();
-      return result;
-    };
-  };
-  // https://github.com/nodejs/node/blob/88f4cef8b96b2bb9d4a92f6848ce4d63a82879a8/lib/internal/readline/interface.js#L954
-  // added in https://github.com/nodejs/node/commit/96be7836d794509dd455e66d91c2975419feed64
-  // handles newlines inside multi-line input and replaces `.displayPrompt()` which was
-  // previously used to print the prompt for multi-line input.
-  const addNewLineOnTTYKey = [...prototypeChain(repl)]
-    .flatMap((proto) => Object.getOwnPropertySymbols(proto))
-    .find((s) => String(s).includes('(_addNewLineOnTTY)')) as keyof REPLServer;
-  wrapMethodWithLineByLineInputNextLine(repl, 'displayPrompt');
-  wrapMethodWithLineByLineInputNextLine(repl, addNewLineOnTTYKey);
-}