diff --git a/node_modules/mdl-ext/es/utils/constants.js b/node_modules/mdl-ext/es/utils/constants.js
new file mode 100644
index 0000000..2d063e2
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+++ b/node_modules/mdl-ext/es/utils/constants.js
@@ -0,0 +1,63 @@
+'use strict';
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+var VK_TAB = 9;
+var VK_ENTER = 13;
+var VK_ESC = 27;
+var VK_SPACE = 32;
+var VK_PAGE_UP = 33;
+var VK_PAGE_DOWN = 34;
+var VK_END = 35;
+var VK_HOME = 36;
+var VK_ARROW_LEFT = 37;
+var VK_ARROW_UP = 38;
+var VK_ARROW_RIGHT = 39;
+var VK_ARROW_DOWN = 40;
+
+var ARIA_EXPANDED = 'aria-expanded';
+var ARIA_HIDDEN = 'aria-hidden';
+var ARIA_MULTISELECTABLE = 'aria-multiselectable';
+var ARIA_SELECTED = 'aria-selected';
+
+var IS_DIRTY = 'is-dirty';
+var IS_DISABLED = 'is-disabled';
+var IS_EXPANDED = 'is-expanded';
+var IS_FOCUSED = 'is-focused';
+var IS_INVALID = 'is-invalid';
+var IS_UPGRADED = 'is-upgraded';
+var DATA_UPGRADED = 'data-upgraded';
+
+var MDL_RIPPLE = 'mdl-ripple';
+var MDL_RIPPLE_COMPONENT = 'MaterialRipple';
+var MDL_RIPPLE_EFFECT = 'mdl-js-ripple-effect';
+var MDL_RIPPLE_EFFECT_IGNORE_EVENTS = 'mdl-js-ripple-effect--ignore-events';
+
+exports.VK_TAB = VK_TAB;
+exports.VK_ENTER = VK_ENTER;
+exports.VK_ESC = VK_ESC;
+exports.VK_SPACE = VK_SPACE;
+exports.VK_PAGE_UP = VK_PAGE_UP;
+exports.VK_PAGE_DOWN = VK_PAGE_DOWN;
+exports.VK_END = VK_END;
+exports.VK_HOME = VK_HOME;
+exports.VK_ARROW_LEFT = VK_ARROW_LEFT;
+exports.VK_ARROW_UP = VK_ARROW_UP;
+exports.VK_ARROW_RIGHT = VK_ARROW_RIGHT;
+exports.VK_ARROW_DOWN = VK_ARROW_DOWN;
+exports.ARIA_EXPANDED = ARIA_EXPANDED;
+exports.ARIA_HIDDEN = ARIA_HIDDEN;
+exports.ARIA_MULTISELECTABLE = ARIA_MULTISELECTABLE;
+exports.ARIA_SELECTED = ARIA_SELECTED;
+exports.IS_DIRTY = IS_DIRTY;
+exports.IS_DISABLED = IS_DISABLED;
+exports.IS_EXPANDED = IS_EXPANDED;
+exports.IS_FOCUSED = IS_FOCUSED;
+exports.IS_INVALID = IS_INVALID;
+exports.IS_UPGRADED = IS_UPGRADED;
+exports.DATA_UPGRADED = DATA_UPGRADED;
+exports.MDL_RIPPLE = MDL_RIPPLE;
+exports.MDL_RIPPLE_COMPONENT = MDL_RIPPLE_COMPONENT;
+exports.MDL_RIPPLE_EFFECT = MDL_RIPPLE_EFFECT;
+exports.MDL_RIPPLE_EFFECT_IGNORE_EVENTS = MDL_RIPPLE_EFFECT_IGNORE_EVENTS;
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