File copy button

.js/default.js

@@ -1,3 +1,15 @@
 function addStyle(style) {
 	$("body").after(`<style>${style}</style>`);
+}
+
+function copyToClipBoard(text) {
+	let textArea = $("<textarea></textarea>");
+	textArea.css("opacity", "0");
+	textArea.css("position", "fixed");
+	textArea.val(text);
+	$("body").append(textArea);
+
+	textArea.select();
+	document.execCommand("copy");
+	textArea.remove();
 }

.js/github.com.js

@@ -185,4 +185,27 @@ let currentUser = $("ul.header-nav.float-right > li:last > a > img").attr("alt")
 			});
 		});
 	});
+})();
+
+// file copy button
+(function() {
+	if (!$("[data-line-number='1']").length) {
+		return;
+	}
+
+	let targetSibling = $("#raw-url")
+	let fileUrl = targetSibling.attr("href");
+
+	let copyBtn = $("<a></a>");
+	copyBtn.text("Copy");
+	copyBtn.attr("href", fileUrl);
+	copyBtn.addClass("btn btn-sm copy-btn");
+
+	copyBtn.click((e) => {
+		e.preventDefault();
+		let fileContents = $(".js-file-line-container").get(0).innerText;
+		copyToClipBoard(fileContents);
+	});
+
+	targetSibling.after(copyBtn);
 })();