Allow falsy values for domData.get

packages/metal-dom/src/domData.js

@@ -1,5 +1,7 @@
 'use strict';
 
+import {isDef} from 'metal';
+
 const METAL_DATA = '__metal_data__';
 
 /**
@@ -21,7 +23,7 @@ class domData {
 		if (!name) {
 			return element[METAL_DATA];
 		}
-		if (!element[METAL_DATA][name] && initialValue) {
+		if (!isDef(element[METAL_DATA][name]) && isDef(initialValue)) {
 			element[METAL_DATA][name] = initialValue;
 		}
 		return element[METAL_DATA][name];
@@ -35,6 +37,24 @@ class domData {
 	static has(element) {
 		return !!element[METAL_DATA];
 	}
+
+	/**
+	 * Sets Metal.js's data for the given element.
+	 * @param {!Element} element
+	 * @param {string=} name Property from the data to be set.
+	 * @param {*=} value Value to be set on the element.
+	 * @return {!Object|*}
+	 */
+	static set(element, name, value) {
+		if (!element[METAL_DATA]) {
+			element[METAL_DATA] = {};
+		}
+		if (!name || !isDef(value)) {
+			return element[METAL_DATA];
+		}
+		element[METAL_DATA][name] = value;
+		return element[METAL_DATA][name];
+	}
 }
 
 export default domData;

packages/metal-dom/test/domData.js

@@ -3,19 +3,102 @@
 import domData from '../src/domData';
 
 describe('domData', function() {
-	it('should get data object from element', function() {
-		let data = domData.get(document.createElement('div'));
-		assert.ok(data);
+	describe('get', function() {
+		it('should get data object from element', function() {
+			let data = domData.get(document.createElement('div'));
+			assert.ok(data);
+		});
+
+		it('should return same data object for the same element', function() {
+			let element = document.createElement('div');
+			assert.strictEqual(domData.get(element), domData.get(element));
+		});
+
+		it('should return different data objects for the different elements', function() {
+			let element1 = document.createElement('div');
+			let element2 = document.createElement('div');
+			assert.notStrictEqual(domData.get(element1), domData.get(element2));
+		});
+
+		it('should set initialValue only if value does not exist', function() {
+			let element = document.createElement('div');
+			let key = domData.get(element, 'key', 'foo');
+			assert.strictEqual(key, 'foo');
+
+			key = domData.get(element, 'key', 'bar');
+			assert.strictEqual(key, 'foo');
+		});
+
+		it('should allow initialValue to be falsy', function() {
+			let element = document.createElement('div');
+			let key = domData.get(element, 'key', 0);
+			assert.strictEqual(key, 0);
+
+			key = domData.get(element, 'key', 1);
+			assert.strictEqual(key, 0);
+		});
+
+		it('should not overwrite initialValue with undefined', function() {
+			let element = document.createElement('div');
+			let key = domData.get(element, 'key', 'foo');
+			assert.strictEqual(key, 'foo');
+
+			key = domData.get(element, 'key');
+			assert.strictEqual(key, 'foo');
+		});
 	});
 
-	it('should return same data object for the same element', function() {
-		let element = document.createElement('div');
-		assert.strictEqual(domData.get(element), domData.get(element));
+	describe('has', function() {
+		it('should return false if no data object exists', function() {
+			let element = document.createElement('div');
+			assert.strictEqual(domData.has(element), false);
+		});
+
+		it('should return true if data object exists', function() {
+			let element = document.createElement('div');
+			domData.get(element);
+			assert.strictEqual(domData.has(element), true);
+		});
 	});
 
-	it('should return different data objects for the different elements', function() {
-		let element1 = document.createElement('div');
-		let element2 = document.createElement('div');
-		assert.notStrictEqual(domData.get(element1), domData.get(element2));
+	describe('set', function() {
+		it('should get data object from element', function() {
+			let element = document.createElement('div');
+			domData.set(element, 'value', 20);
+			let data = domData.get(element);
+			assert.deepEqual(data, {
+				value: 20,
+			});
+		});
+
+		it('should get data value from element', function() {
+			let element = document.createElement('img');
+			domData.set(element, 'value', true);
+			let data = domData.get(element, 'value');
+			assert.strictEqual(data, true);
+		});
+
+		it('should create data object without a value', function() {
+			let element = document.createElement('div');
+			domData.set(element);
+			let data = domData.get(element);
+			assert.deepEqual(data, {});
+		});
+
+		it('should overwrite a data value using set', function() {
+			let element = document.createElement('div');
+			domData.set(element, 'value', true);
+			assert.strictEqual(domData.get(element, 'value'), true);
+			domData.set(element, 'value', 20);
+			assert.strictEqual(domData.get(element, 'value'), 20);
+		});
+
+		it('should set falsy value', function() {
+			let element = document.createElement('div');
+			domData.set(element, 'value', false);
+			assert.strictEqual(domData.get(element, 'value'), false);
+			domData.set(element, 'value', 0);
+			assert.strictEqual(domData.get(element, 'value'), 0);
+		});
 	});
 });