remove or edit attributes

Author: goto-bus-stop

index.js

@@ -232,7 +232,12 @@ function addAttrs (str, existing, update) {
   var k = Object.keys(newAttrs)
   for (var i = 0; i < k.length; i++) {
     if (k[i][0] === '_') continue
+
     var value = newAttrs[k[i]]
+    if (typeof value === 'function') value = value(existing[k[i]] || '')
+
+    if (value == null) continue
+
     attrs.push(' ' + k[i] + '="')
     if (typeof value === 'object' && !isStream(value)) {
       if (value.prepend) attrs.push(value.prepend)

test/attrs.js

@@ -1,5 +1,6 @@
 var test = require('tape')
 var concat = require('simple-concat')
+var through = require('through2')
 var hyperstream = require('../')
 
 test('add an attribute', function (t) {
@@ -26,6 +27,18 @@ test('replace an attribute', function (t) {
   hs.end('<div class="it did not work" id="a"></div>')
 })
 
+test('remove attribute', function (t) {
+  var hs = hyperstream({
+    '#a': { class: null }
+  })
+  concat(hs, function (err, result) {
+    t.ifError(err)
+    t.equal(result + '', '<div id="a"></div>')
+    t.end()
+  })
+  hs.end('<div class="it did not work" id="a"></div>')
+})
+
 test('prepend to attribute', function (t) {
   var hs = hyperstream({
     '#a': { class: { prepend: 'it ' } }
@@ -49,3 +62,41 @@ test('append to attribute', function (t) {
   })
   hs.end('<div class="it" id="a"></div>')
 })
+
+test('edit attribute', function (t) {
+  var hs = hyperstream({
+    '#a': {
+      class: function (original) {
+        return original.toUpperCase()
+      }
+    }
+  })
+  concat(hs, function (err, result) {
+    t.ifError(err)
+    t.equal(result + '', '<div class="CLASSNAME" id=a></div>')
+    t.end()
+  })
+  hs.end('<div class="classname" id=a></div>')
+})
+
+test('edit attribute with streams', function (t) {
+  var hs = hyperstream({
+    '#a': {
+      class: function (initial) {
+        var stream = through(function (chunk, enc, cb) {
+          cb()
+        }, function (cb) {
+          cb(null, 'beep boop')
+        })
+        stream.end(initial)
+        return stream
+      }
+    }
+  })
+  concat(hs, function (err, result) {
+    t.ifError(err)
+    t.equal(result + '', '<div class="beep boop" id=a></div>')
+    t.end()
+  })
+  hs.end('<div class="classname" id=a></div>')
+})