readline,repl: skip history entries identical to the current line

Skip history entries that are identical to the currently visible line
to improve the user experience.

PR-URL: https://github.com/nodejs/node/pull/31112
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/readline.js

@@ -702,7 +702,8 @@ Interface.prototype._historyNext = function() {
     const search = this[kSubstringSearch] || '';
     let index = this.historyIndex - 1;
     while (index >= 0 &&
-           !this.history[index].startsWith(search)) {
+           (!this.history[index].startsWith(search) ||
+             this.line === this.history[index])) {
       index--;
     }
     if (index === -1) {
@@ -721,10 +722,13 @@ Interface.prototype._historyPrev = function() {
     const search = this[kSubstringSearch] || '';
     let index = this.historyIndex + 1;
     while (index < this.history.length &&
-           !this.history[index].startsWith(search)) {
+           (!this.history[index].startsWith(search) ||
+             this.line === this.history[index])) {
       index++;
     }
     if (index === this.history.length) {
+      // TODO(BridgeAR): Change this to:
+      // this.line = search;
       return;
     } else {
       this.line = this.history[index];

test/parallel/test-repl-history-navigation.js

@@ -138,11 +138,7 @@ const tests = [
       // UP - skipping const foo = true
       '\x1B[1G', '\x1B[0J',
       '> 555 + 909', '\x1B[12G',
-      // UP - matching the identical history entry again.
-      '\x1B[1G', '\x1B[0J',
-      '> 555 + 909',
       // UP, UP, ENTER. UPs at the end of the history have no effect.
-      '\x1B[12G',
       '\r\n',
       '1464\n',
       '\x1B[1G', '\x1B[0J',