ansi-scrollbox - npm Package Compare versions

Comparing version 0.1.0 to 0.2.0

CHANGELOG.md

@@ -7,3 +7,8 @@ # ansi-scrollbox change log
 
+## 0.2.0
+* Calculate all scrolling from the start of the content.
+  Previously scrolling to the end, then back up, would calculate scrolling from the end of the content, so the content would autoscroll as it was updated. Now ansi-scrollbox only autoscrolls if you're at the very bottom.
+* Add a `subscribe(listener)` API to listen for updates to content, size or scroll
+
 ## 0.1.0
 * Initial (pretty beta) release.

example.js

@@ -38,3 +38,3 @@ var scrollbox = require('./')
 write()
-setInterval(write, 100)
+box.subscribe(write)
 
@@ -41,0 +41,0 @@ // make `process.stdin` begin emitting "keypress" events

index.js

@@ -7,12 +7,22 @@ var assert = require('assert')
   assert.equal(typeof opts, 'object', 'opts must be object')
+
+  // user facing state
   var content = opts.content || ''
   var width = opts.width
   var height = opts.height
+
+  // list of lines (split `content` according to `width`)
+  // so we can easily show parts of the scrollable content
   var lines = []
-  var linesDirty = false
+  var linesDirty = false // if true `lines` needs to be updated before use
 
+  var sub = Subscribable()
+
   var instance = {
+    subscribe: sub.subscribe,
     setContent: setContent,
     resize: resize,
     scroll: scroll,
+    scrollUp: scrollUp,
+    scrollDown: scrollDown,
     keypress: keypress,
@@ -33,2 +43,3 @@ toString: toString,
     linesDirty = true
+    sub.notify()
   }
@@ -44,2 +55,3 @@
     linesDirty = true
+    sub.notify()
   }
@@ -51,5 +63,12 @@
     offset = _offset
+    sub.notify()
   }
+  function scrollUp (d) {
+    scroll(offset < 0 ? offset - d : Math.max(offset - d, 0))
+  }
+  function scrollDown (d) {
+    scroll(offset >= 0 ? offset + d : Math.min(offset + d, -1))
+  }
 
-  // TODO optimize
+  // TODO optimize somehow
   function updateLinesCache () {
@@ -60,6 +79,20 @@ lines = wrapAnsi(content, width, { wordWrap: false }).split('\n')
 
+  // ensure `offset` is an in-range scroll offset (first visible line index)
+  // or -1 (stick to bottom)
+  function resolveOffset () {
+    if (offset === -1) return
+    if (offset >= lines.length - height) {
+      offset = Math.max(0, lines.length - height)
+    } else if (offset < -1) {
+      offset = Math.max(0, lines.length + offset + 1 - height)
+    }
+  }
+
   function toString () {
     if (linesDirty) updateLinesCache()
-    var o = offset < 0 ? lines.length - height + offset : Math.min(lines.length - height, offset)
+    resolveOffset()
+
+    var o = offset === -1 ? lines.length - height : Math.min(lines.length - height, offset)
     var visible = lines.slice(o, o + height)
+    // fill the rest of the space so height doesn't vary
     while (visible.length < height) visible.push('')
@@ -72,6 +105,6 @@ return visible.join('\n')
     if (key.name === 'down' || key.name === 'j') {
-      offset = offset >= 0 ? offset + 1 : Math.min(offset + 1, -1)
+      scrollDown(1)
     }
     if (key.name === 'up' || key.name === 'k') {
-      offset = offset < 0 ? offset - 1 : Math.max(offset - 1, 0)
+      scrollUp(1)
     }
@@ -84,1 +117,21 @@ if (key.name === 'home') offset = 0
 }
+
+function Subscribable () {
+  var listeners = []
+
+  function subscribe (fn) {
+    listeners.push(fn)
+    return function () {
+      var i = listeners.indexOf(fn)
+      if (i !== -1) listeners.splice(i, 1)
+    }
+  }
+  function notify () {
+    listeners.forEach(function (fn) { fn() })
+  }
+
+  return {
+    subscribe: subscribe,
+    notify: notify
+  }
+}

package.json

 {
   "name": "ansi-scrollbox",
   "description": "a basic scrollable area for terminal apps",
-  "version": "0.1.0",
+  "version": "0.2.0",
   "author": "Renée Kooi <[e-mail]>",
@@ -6,0 +6,0 @@ "bugs": {

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Improved metrics

Total package byte prevSize

8361

increased by23.83%

Lines of code

164

increased by37.82%

No dependency changes