wip: code formatting nits continued

test/bindKey.spec.js

@@ -0,0 +1,65 @@
+import { slice } from './utils';
+import bindKey from '../src/bindKey';
+
+describe('bindKey', () => {
+    it('should work when the target function is overwritten', () => {
+        const object = {
+            user: 'fred',
+            greet: function (greeting) {
+                return `${this.user} says: ${greeting}`;
+            },
+        };
+
+        const bound = bindKey(object, 'greet', 'hi');
+        expect(bound()).toBe('fred says: hi');
+
+        object.greet = function (greeting) {
+            return `${this.user} says: ${greeting}!`;
+        };
+
+        expect(bound()).toBe('fred says: hi!');
+    });
+
+    it('should support placeholders', () => {
+        const object = {
+            fn: function () {
+                return slice.call(arguments);
+            },
+        };
+
+        const ph = bindKey.placeholder;
+        const bound = bindKey(object, 'fn', ph, 'b', ph);
+
+        expect(bound('a', 'c'), ['a', 'b').toEqual('c']);
+        expect(bound('a'), ['a', 'b').toEqual(undefined]);
+        expect(bound('a', 'c', 'd'), ['a', 'b', 'c').toEqual('d']);
+        expect(bound(), [undefined, 'b').toEqual(undefined]);
+    });
+
+    it('should use `_.placeholder` when set', () => {
+        const object = {
+            fn: function () {
+                return slice.call(arguments);
+            },
+        };
+
+        const _ph = (_.placeholder = {});
+        const ph = bindKey.placeholder;
+        const bound = bindKey(object, 'fn', _ph, 'b', ph);
+
+        expect(bound('a', 'c'), ['a', 'b', ph).toEqual('c']);
+        delete _.placeholder;
+    });
+
+    it('should ensure `new bound` is an instance of `object[key]`', () => {
+        function Foo(value) {
+            return value && object;
+        }
+
+        var object = { Foo: Foo };
+        const bound = bindKey(object, 'Foo');
+
+        expect(new bound() instanceof Foo)
+        expect(new bound(true)).toBe(object);
+    });
+});