Isolate actions strategies in order to code improvement and programmatic usage. (#749)

* Isolate cut, copy and core helper functions.

* Update tests to accommodate new proposal

* Add/update tests

* Add tests to static copy/cut methods

* Update condition syntax based on PR reviews

* Migrate clipboard-action-default to functional approach. Update tests. Add tests

* Improve folder structure. Clean up code.

* Add types. Fix tsd check env. Improve in-code doc comments

* Improve in-code doc comments

test/actions/copy.js

@@ -0,0 +1,55 @@
+import ClipboardActionCopy from '../../src/actions/copy';
+
+describe('ClipboardActionCopy', () => {
+  before(() => {
+    global.input = document.createElement('input');
+    global.input.setAttribute('id', 'input');
+    global.input.setAttribute('value', 'abc');
+    document.body.appendChild(global.input);
+
+    global.paragraph = document.createElement('p');
+    global.paragraph.setAttribute('id', 'paragraph');
+    global.paragraph.textContent = 'abc';
+    document.body.appendChild(global.paragraph);
+  });
+
+  after(() => {
+    document.body.innerHTML = '';
+  });
+
+  describe('#selectText', () => {
+    it('should select its value based on input target', () => {
+      const selectedText = ClipboardActionCopy(
+        document.querySelector('#input'),
+        {
+          container: document.body,
+        }
+      );
+
+      assert.equal(selectedText, document.querySelector('#input').value);
+    });
+
+    it('should select its value based on element target', () => {
+      const selectedText = ClipboardActionCopy(
+        document.querySelector('#paragraph'),
+        {
+          container: document.body,
+        }
+      );
+
+      assert.equal(
+        selectedText,
+        document.querySelector('#paragraph').textContent
+      );
+    });
+
+    it('should select its value based on text', () => {
+      const text = 'abc';
+      const selectedText = ClipboardActionCopy(text, {
+        container: document.body,
+      });
+
+      assert.equal(selectedText, text);
+    });
+  });
+});