CMS: Grapesjs is not defined

I am trying to use basic Grapesjs editor to CMS. Here's my code:

<link href="https://unpkg.com/grapesjs/dist/css/grapes.min.css" rel="stylesheet">
<script src="https://unpkg.com/[email protected]/dist/grapes.js"></script>
<style>
    body,
    html {
        height: 100%;
        margin: 0;
    }
</style>

<div id="gjs" style="height:0px; overflow:hidden">
    <div style="margin:100px 100px 25px; padding:25px; font:caption"> This is a sample text</div>
</div>


<script type="text/javascript">
    alert('Start');
    var editor = grapesjs.init({
        height: '100%',
        showOffsets: 1,
        noticeOnUnload: 0,
        storageManager: {autoload: 0},
        container: '#gjs',
        fromElement: true,

        plugins: ['gjs-blocks-basic', 'gjs-plugin-actions'],
        pluginsOpts: {
            'gjs-plugin-actions': {},
            'gjs-blocks-basic': {
                flexGrid: 1
            }
        }
    });
    window.editor = editor;
    alert('end');
</script>

I have installed the grapesjs using NPM. Later I tried running this html file in the local, as expected the output was Grapesjs editor. I used this same file in CMS and I am getting grapesjs is not defined.