CSS: implement prettier-ignore (#2089)

* fix(css): implement prettier-ignore, fixes #2007

* refactor(css): move prettier-ignore to printNodeSequence

src/printer-postcss.js

@@ -337,7 +337,23 @@ function printNodeSequence(path, options, print) {
   const parts = [];
   let i = 0;
   path.map(pathChild => {
-    parts.push(pathChild.call(print));
+    const prevNode = node.nodes[i - 1];
+    if (
+      prevNode &&
+      prevNode.type === "css-comment" &&
+      prevNode.text.trim() === "prettier-ignore"
+    ) {
+      const childNode = pathChild.getValue();
+      parts.push(
+        options.originalText.slice(
+          util.locStart(childNode),
+          util.locEnd(childNode)
+        )
+      );
+    } else {
+      parts.push(pathChild.call(print));
+    }
+
     if (i !== node.nodes.length - 1) {
       if (
         (node.nodes[i + 1].type === "css-comment" &&

tests/css_comments/__snapshots__/jsfmt.spec.js.snap

@@ -67,6 +67,29 @@ div {
 
 `;
 
+exports[`prettier-ignore.css 1`] = `
+// prettier-ignore
+@blue:  blue;
+@black: darkgray;
+
+foo {
+  /* prettier-ignore */
+  thing:     foo;
+  -ms-thing: foo;
+}
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+// prettier-ignore
+@blue:  blue;
+@black: darkgray;
+
+foo {
+  /* prettier-ignore */
+  thing:     foo;
+  -ms-thing: foo;
+}
+
+`;
+
 exports[`selector.css 1`] = `
 .powerPathNavigator .helm button.pressedButton, /* pressed buttons */
 .powerPathNavigator .helm button:active:not(.disabledButton),

tests/css_comments/prettier-ignore.css

@@ -0,0 +1,9 @@
+// prettier-ignore
+@blue:  blue;
+@black: darkgray;
+
+foo {
+  /* prettier-ignore */
+  thing:     foo;
+  -ms-thing: foo;
+}