readline: name some anonymous functions

PR-URL: https://github.com/nodejs/node/pull/14297
Refs: https://github.com/nodejs/node/issues/8913
Refs: https://github.com/nodejs/node/pull/14297#pullrequestreview-50206772
Reviewed-By: Khaidi Chu <i@2333.moe>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

lib/readline.js

@@ -130,9 +130,11 @@ function Interface(input, output, completer, terminal) {
 
   // Check arity, 2 - for async, 1 for sync
   if (typeof completer === 'function') {
-    this.completer = completer.length === 2 ? completer : function(v, cb) {
-      cb(null, completer(v));
-    };
+    this.completer = completer.length === 2 ?
+      completer :
+      function completerWrapper(v, cb) {
+        cb(null, completer(v));
+      };
   }
 
   this.setPrompt(prompt);
@@ -175,15 +177,23 @@ function Interface(input, output, completer, terminal) {
   }
 
   if (!this.terminal) {
-    input.on('data', ondata);
-    input.on('end', onend);
-    self.once('close', function() {
+    function onSelfCloseWithoutTerminal() {
       input.removeListener('data', ondata);
       input.removeListener('end', onend);
-    });
-    this._decoder = new StringDecoder('utf8');
+    }
 
+    input.on('data', ondata);
+    input.on('end', onend);
+    self.once('close', onSelfCloseWithoutTerminal);
+    this._decoder = new StringDecoder('utf8');
   } else {
+    function onSelfCloseWithTerminal() {
+      input.removeListener('keypress', onkeypress);
+      input.removeListener('end', ontermend);
+      if (output !== null && output !== undefined) {
+        output.removeListener('resize', onresize);
+      }
+    }
 
     emitKeypressEvents(input, this);
 
@@ -206,13 +216,7 @@ function Interface(input, output, completer, terminal) {
     if (output !== null && output !== undefined)
       output.on('resize', onresize);
 
-    self.once('close', function() {
-      input.removeListener('keypress', onkeypress);
-      input.removeListener('end', ontermend);
-      if (output !== null && output !== undefined) {
-        output.removeListener('resize', onresize);
-      }
-    });
+    self.once('close', onSelfCloseWithTerminal);
   }
 
   input.resume();
@@ -460,7 +464,7 @@ Interface.prototype._tabComplete = function(lastKeypressWasTab) {
   var self = this;
 
   self.pause();
-  self.completer(self.line.slice(0, self.cursor), function(err, rv) {
+  self.completer(self.line.slice(0, self.cursor), function onComplete(err, rv) {
     self.resume();
 
     if (err) {
@@ -474,7 +478,7 @@ Interface.prototype._tabComplete = function(lastKeypressWasTab) {
       // Apply/show completions.
       if (lastKeypressWasTab) {
         self._writeToOutput('\r\n');
-        var width = completions.reduce(function(a, b) {
+        var width = completions.reduce(function completionReducer(a, b) {
           return a.length > b.length ? a : b;
         }).length + 2;  // 2 space padding
         var maxColumns = Math.floor(self.columns / width);
@@ -495,7 +499,9 @@ Interface.prototype._tabComplete = function(lastKeypressWasTab) {
       }
 
       // If there is a common prefix to all matches, then apply that portion.
-      var f = completions.filter(function(e) { if (e) return e; });
+      var f = completions.filter(function completionFilter(e) {
+        if (e) return e;
+      });
       var prefix = commonPrefix(f);
       if (prefix.length > completeOn.length) {
         self._insertString(prefix.slice(completeOn.length));