Add d3.create. Fixes #156.

Author: mbostock

README.md

@@ -428,6 +428,10 @@ selection.each(function() {
 });
 ```
 
+<a name="create" href="#create">#</a> d3.<b>create</b>(<i>name</i>) [<>](https://github.com/d3/d3-selection/blob/master/src/create.js "Source")
+
+Given the specified element *name*, returns a single-element selection containing a detached element of the given name in the current document.
+
 <a name="creator" href="#creator">#</a> d3.<b>creator</b>(<i>name</i>) [<>](https://github.com/d3/d3-selection/blob/master/src/creator.js "Source")
 
 Given the specified element *name*, returns a function which creates an element of the given name, assuming that `this` is the parent element. This method is used internally by [*selection*.append](#selection_append) and [*selection*.insert](#selection_insert) to create new elements. For example, this:

index.js

@@ -1,3 +1,4 @@
+export {default as create} from "./src/create";
 export {default as creator} from "./src/creator";
 export {default as local} from "./src/local";
 export {default as matcher} from "./src/matcher";

src/create.js

@@ -0,0 +1,6 @@
+import creator from "./creator";
+import select from "./select";
+
+export default function(name) {
+  return select(creator(name).call(document.documentElement));
+}

test/create-test.js

@@ -0,0 +1,29 @@
+var tape = require("tape"),
+    jsdom = require("./jsdom"),
+    d3 = require("../");
+
+tape("d3.create(name) returns a new HTML element with the given name", function(test) {
+  var document = global.document = jsdom("");
+  try {
+    var h1 = d3.create("h1");
+    test.equal(h1._groups[0][0].namespaceURI, "http://www.w3.org/1999/xhtml");
+    test.equal(h1._groups[0][0].tagName, "H1");
+    test.deepEqual(h1._parents, [null]);
+    test.end();
+  } finally {
+    delete global.document;
+  }
+});
+
+tape("d3.create(name) returns a new SVG element with the given name", function(test) {
+  var document = global.document = jsdom("");
+  try {
+    var svg = d3.create("svg");
+    test.equal(svg._groups[0][0].namespaceURI, "http://www.w3.org/2000/svg");
+    test.equal(svg._groups[0][0].tagName, "svg");
+    test.deepEqual(svg._parents, [null]);
+    test.end();
+  } finally {
+    delete global.document;
+  }
+});