Initial commit

.gitignore

@@ -0,0 +1 @@
+node_modules

Makefile

@@ -0,0 +1,7 @@
+
+test:
+	@./node_modules/.bin/mocha \
+		--require should \
+		--reporter spec
+
+.PHONY: test

Readme.md

@@ -0,0 +1,44 @@
+
+# History
+
+  Keep track of and cycle through history, for example chat messages.
+
+## Installation
+
+```
+$ component install component/history
+```
+
+## API
+
+### History(vals)
+
+  Initialize with an array of `vals`.
+
+### History#add(val)
+
+  Add a value, for example a chat message or REPL command line.
+  This method resets the history index, meaning the next call
+  to `.back()` will be this latest value.
+
+### History#back()
+
+  Cycle backwards through history, returning a value added by `.add()`.
+  When the end of history is reached `undefined` is returned. 
+
+### History#back()
+
+  Cycle forwards through history, returning a value added by `.add()`.
+  When the end of history is reached `undefined` is returned. 
+
+### History#max(n)
+
+  The maximum number of entries defaulting to `1000`.
+
+### History#reset()
+
+  Reset the index to the latest value.
+
+## License
+
+  MIT

component.json

@@ -0,0 +1,7 @@
+{
+  "name": "history",
+  "description": "Keep track of and cycle through history",
+  "keywords": ["history"],
+  "version": "0.0.1",
+  "scripts": ["index.js"]
+}

index.js

@@ -0,0 +1,96 @@
+
+/**
+ * Expose `History`.
+ */
+
+module.exports = History;
+
+/**
+ * Initialize a `History` with the given `vals`.
+ *
+ * @param {Array} vals
+ * @api public
+ */
+
+function History(vals) {
+  this.vals = vals || [];
+  this.reset();
+  this.max(1000);
+}
+
+/**
+ * Cap the entries.
+ *
+ * @api private
+ */
+
+History.prototype.cap = function(){
+  var max = this._max;
+  var len = this.vals.length;
+  var remove = len - max;
+  if (remove <= 0) return;
+  while (remove--) this.vals.shift();
+  this.reset();
+};
+
+/**
+ * Set the maximum number of entries to `n`.
+ *
+ * @param {Number} n
+ * @return {History}
+ * @api public
+ */
+
+History.prototype.max = function(n){
+  this._max = n;
+  this.cap();
+  return this;
+};
+
+/**
+ * Add a `val`.
+ *
+ * @param {Object} val
+ * @return {History}
+ * @api public
+ */
+
+History.prototype.add = function(val){
+  this.i = this.vals.push(val) - 1;
+  this.cap();
+  return this;
+};
+
+/**
+ * Cycle backwards through history.
+ *
+ * @return {Object}
+ * @api public
+ */
+
+History.prototype.back = function(){
+  return this.vals[this.i--];
+};
+
+/**
+ * Cycle forward through history.
+ *
+ * @return {Object}
+ * @api public
+ */
+
+History.prototype.forward = function(){
+  return this.vals[++this.i];
+};
+
+/**
+ * Reset the history index.
+ *
+ * @return {History}
+ * @api public
+ */
+
+History.prototype.reset = function(){
+  this.i = this.vals.length - 1;
+  return this;
+};

package.json

@@ -0,0 +1,14 @@
+{
+  "name": "history-component",
+  "description": "Keep track of and cycle through history",
+  "version": "0.0.1",
+  "devDependencies": {
+    "mocha": "*",
+    "should": "*"
+  },
+  "component": {
+    "scripts": {
+      "history": "index.js"
+    }
+  }
+}

test/history.js

@@ -0,0 +1,98 @@
+
+var History = require('..')
+  , assert = require('assert');
+
+describe('History', function(){
+  describe('(arr)', function(){
+    it('should populate the history', function(){
+      var history = new History(['foo', 'bar', 'baz']);
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+      history.back().should.equal('foo');
+    })
+  })
+
+  describe('.add(obj)', function(){
+    it('should add to the history', function(){
+      var history = new History;
+      history.add('foo');
+      history.add('bar');
+      history.add('baz');
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+      history.back().should.equal('foo');
+    })
+
+    it('should reset the index', function(){
+      var history = new History;
+      history.add('foo');
+      history.add('bar');
+      history.add('baz');
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+      history.add('hey');
+      history.back().should.equal('hey');
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+    })
+  })
+
+  describe('.back()', function(){
+    it('should cycle through the history', function(){
+      var history = new History;
+      history.add('foo');
+      history.add('bar');
+      history.add('baz');
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+      history.back().should.equal('foo');
+    })
+
+    it('should return undefined at the end', function(){
+      var history = new History;
+      history.add('foo');
+      history.back().should.equal('foo');
+      assert(undefined === history.back());
+    })
+  })
+
+  describe('.forward()', function(){
+    it('should cycle through the history', function(){
+      var history = new History;
+      history.add('foo');
+      history.add('bar');
+      history.add('baz');
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+      history.back().should.equal('foo');
+      history.forward().should.equal('foo');
+      history.forward().should.equal('bar');
+      history.forward().should.equal('baz');
+    })
+
+    it('should return undefined at the end', function(){
+      var history = new History;
+      history.add('foo');
+      assert(undefined === history.forward());
+    })
+  })
+
+  describe('.max(n)', function(){
+    it('should cap the history entries', function(){
+      var history = new History;
+      history.max(2);
+      history.add('foo');
+      history.add('bar');
+      history.add('baz');
+
+      history.back().should.equal('baz');
+      history.back().should.equal('bar');
+      assert(null == history.back());
+
+      history.add('raz');
+      history.back().should.equal('raz');
+      history.back().should.equal('baz');
+      assert(null == history.back());
+    })
+  })
+})