luci-base: luci.js: add Promise.finally polyfill

Fixes: #2854
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/modules/luci-base/htdocs/luci-static/resources/luci.js b/modules/luci-base/htdocs/luci-static/resources/luci.js
index 6659bc51b6..259679f137 100644
--- a/modules/luci-base/htdocs/luci-static/resources/luci.js
+++ b/modules/luci-base/htdocs/luci-static/resources/luci.js
@@ -23,6 +23,20 @@
 		});
 	}
 
+	/* Promise.finally polyfill */
+	if (typeof Promise.prototype.finally !== 'function') {
+		Promise.prototype.finally = function(fn) {
+			var onFinally = function(cb) {
+				return Promise.resolve(fn.call(this)).then(cb);
+			};
+
+			return this.then(
+				function(result) { return onFinally.call(this, function() { return result }) },
+				function(reason) { return onFinally.call(this, function() { return Promise.reject(reason) }) }
+			);
+		};
+	}
+
 	/*
 	 * Class declaration and inheritance helper
 	 */