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/default.js

@@ -0,0 +1,80 @@
+import ClipboardActionDefault from '../../src/actions/default';
+
+describe('ClipboardActionDefault', () => {
+  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('#resolveOptions', () => {
+    it('should set base properties', () => {
+      const selectedText = ClipboardActionDefault({
+        container: document.body,
+        text: 'foo',
+      });
+
+      assert.equal(selectedText, 'foo');
+    });
+  });
+
+  describe('#set action', () => {
+    it('should throw an error since "action" is invalid', (done) => {
+      try {
+        let clip = ClipboardActionDefault({
+          text: 'foo',
+          action: 'paste',
+        });
+      } catch (e) {
+        assert.equal(
+          e.message,
+          'Invalid "action" value, use either "copy" or "cut"'
+        );
+        done();
+      }
+    });
+  });
+
+  describe('#set target', () => {
+    it('should throw an error since "target" do not match any element', (done) => {
+      try {
+        let clip = ClipboardActionDefault({
+          target: document.querySelector('#foo'),
+        });
+      } catch (e) {
+        assert.equal(e.message, 'Invalid "target" value, use a valid Element');
+        done();
+      }
+    });
+  });
+
+  describe('#selectedText', () => {
+    it('should select text from editable element', () => {
+      const selectedText = ClipboardActionDefault({
+        container: document.body,
+        target: document.querySelector('#input'),
+      });
+
+      assert.equal(selectedText, 'abc');
+    });
+
+    it('should select text from non-editable element', () => {
+      const selectedText = ClipboardActionDefault({
+        container: document.body,
+        target: document.querySelector('#paragraph'),
+      });
+
+      assert.equal(selectedText, 'abc');
+    });
+  });
+});