readline: Allow history to be disabled

doc/api/readline.md

@@ -300,7 +300,8 @@ the following values:
  treated like a TTY, and have ANSI/VT100 escape codes written to it.
  Defaults to checking `isTTY` on the `output` stream upon instantiation.
 
- - `historySize` - maximum number of history lines retained. Defaults to `30`.
+ - `historySize` - maximum number of history lines retained. To disable the
+ history set this value to `0`. Defaults to `30`.
 
 The `completer` function is given the current line entered by the user, and
 is supposed to return an Array with 2 entries:

lib/readline.js

@@ -53,12 +53,15 @@ function Interface(input, output, completer, terminal) {
  historySize = input.historySize;
  input = input.input;
  }
- historySize = historySize || kHistorySize;
 
  if (completer && typeof completer !== 'function') {
  throw new TypeError('Argument "completer" must be a function');
  }
 
+ if (historySize === undefined) {
+ historySize = kHistorySize;
+ }
+
  if (typeof historySize !== 'number' ||
  isNaN(historySize) ||
  historySize < 0) {
@@ -228,6 +231,9 @@ Interface.prototype._writeToOutput = function _writeToOutput(stringToWrite) {
 Interface.prototype._addHistory = function() {
  if (this.line.length === 0) return '';
 
+ // if the history is disabled then return the line
+ if (this.historySize === 0) return this.line;
+
  if (this.history.length === 0 || this.history[0] !== this.line) {
  this.history.unshift(this.line);
 

test/parallel/test-readline-interface.js

@@ -27,6 +27,25 @@ function isWarned(emitter) {
  var rli;
  var called;
 
+ // disable history
+ fi = new FakeInput();
+ rli = new readline.Interface({ input: fi, output: fi, terminal: terminal,
+ historySize: 0 });
+ assert.strictEqual(rli.historySize, 0);
+
+ fi.emit('data', 'asdf\n');
+ assert.deepStrictEqual(rli.history, terminal ? [] : undefined);
+ rli.close();
+
+ // default history size 30
+ fi = new FakeInput();
+ rli = new readline.Interface({ input: fi, output: fi, terminal: terminal});
+ assert.strictEqual(rli.historySize, 30);
+
+ fi.emit('data', 'asdf\n');
+ assert.deepStrictEqual(rli.history, terminal ? ['asdf'] : undefined);
+ rli.close();
+
  // sending a full line
  fi = new FakeInput();
  rli = new readline.Interface({ input: fi, output: fi, terminal: terminal });