docs: Add programmatical usage example

Thor-x86 · Thor-x86 · commit 8840ccf9fa49 · 2021-03-16T08:49:16.000+07:00
diff --git a/README.md b/README.md
@@ -43,6 +43,10 @@ For other than React-based web project, you can still use XML data and compose i
 
 Embedding XML into HTML is now possible for CompoDrawJS. See [the example](https://github.com/Thor-x86/compodraw-js/blob/dev/examples/usage-with-dom.md).
 
+## Use only with JavaScript
+
+For logic-based composition, you can compose Instructs directly without `composeWith*` function. See [the example](https://github.com/Thor-x86/compodraw-js/blob/dev/examples/usage-programmatical.md).
+
 ## How to Contribute
 
 You are free to contribute by opening an issue or pull-request. But before pull-request, it's better to test your changes locally with this command:
diff --git a/examples/usage-programmatical.md b/examples/usage-programmatical.md
@@ -0,0 +1,74 @@
+# Example with Programmatical Method
+
+**NOTE:** In this example, we're assuming you are using [compodraw-instructs](https://github.com/Thor-x86/compodraw-js-instructs).
+
+This method is suitable for logic-based composition. On this example, we don't use any framework. However, you can implement this on any framework that currently you're using.
+
+There is 3 files in a single folder:
+- `index.html` -> Your HTML file
+- `compodraw.js` -> CompoDraw bundled javascript file -- [download](https://github.com/Thor-x86/compodraw-js/releases)
+- `compodraw-instructs.js` -> bundled instructs package -- [download](https://github.com/Thor-x86/compodraw-js-instructs/releases)
+
+Then write this snippet code to `index.html`:
+
+```html
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>CompoDraw Example with XML</title>
+        <style>
+            html, body, canvas {
+                width: 100vw;
+                height: 100vh;
+                margin: 0;
+                padding: 0;
+                overflow: hidden;
+            }
+
+            * {
+                box-sizing: border-box;
+            }
+        </style>
+    </head>
+    <body>
+        <canvas id="viewport">
+            <strong>Canvas is NOT supported!</strong>
+        </canvas>
+
+        <!-- Load the bundled JavaScripts -->
+        <!-- make sure they are in the same folder -->
+        <script src="compodraw.js"></script>
+        <script src="compodraw-instructs.js"></script>
+
+        <script>
+            // If instructs package name contains
+            // dash character "-", make an alias for it
+            const instructs = self['compodraw-instructs'].all;
+
+            // Compose logically
+            const composed = new instructs.Elevate();
+            for(let i = 0; i < 10; i++) {
+                const color = i * 255 / 10;
+                const rectangle = new instructs.Rectangle();
+                rectangle.x = 20 + (120 * i);
+                rectangle.y = 20;
+                rectangle.color = `rgba(${color},${color},${color},1)`;
+                composed.content.push(rectangle);
+            }
+
+            // Get the canvas element
+            const element = document.getElementById('viewport');
+
+            // Redraw on browser window resize,
+            // otherwise it will stretches
+            window.onresize = () => {
+                compodraw.draw(composed, element);
+            };
+
+            // Now, let's draw the canvas!
+            compodraw.draw(composed, element);
+        </script>
+
+    </body>
+</html>
+```
