Remove exception on non-node

Author: wooorm

index.js

@@ -2,19 +2,27 @@
 
 module.exports = toString
 
-// Get the text content of a node.  If the node itself does not expose
-// plain-text fields, `toString` will recursivly try its children.
+// Get the text content of a node.
+// Prefer the node’s plain-text fields, otherwise serialize its children.
 function toString(node) {
   return (
-    valueOf(node) ||
-    (node.children && node.children.map(toString).join('')) ||
+    (node &&
+      (node.value ||
+        node.alt ||
+        node.title ||
+        ('children' in node && all(node.children)))) ||
     ''
   )
 }
 
-// Get the value of `node`.  Checks, `value`, `alt`, and `title`, in that order.
-function valueOf(node) {
-  return (
-    (node && node.value ? node.value : node.alt ? node.alt : node.title) || ''
-  )
+function all(values) {
+  var result = []
+  var length = values.length
+  var index = -1
+
+  while (++index < length) {
+    result[index] = toString(values[index])
+  }
+
+  return result.join('')
 }

test.js

@@ -4,9 +4,8 @@ var test = require('tape')
 var toString = require('.')
 
 test('mdast-util-to-string', function(t) {
-  t.throws(function() {
-    toString()
-  }, 'should fail without node')
+  t.equal(toString(), '', 'should not fail on a missing node')
+  t.equal(toString(null), '', 'should not fail on `null` missing node')
 
   t.equal(
     toString({value: 'foo'}),