Dynamically load external javascript file from Angular component

I am creating an Angular application using Angular 4 and the CLI. I am trying to add the SkyScanner search widget into one of my components.

Skyscanner Widget Example

Part of the implementation requires the addition of a new external script:

<script src="https://widgets.skyscanner.net/widget-server/js/loader.js" async></script>

I am not sure of the correct way to reference this file. If I add the script into my index.html file, the widget doesn't load unless a full page refresh is performed. I assume the script tries to manipulate the DOM on load and the elements don't exist when the script runs.

What is the correct way to load the script only when the component containing the Skyscanner widget is loaded?

Try to load external JavaScript on component load as below :

loadAPI: Promise<any>;

constructor() {        
    this.loadAPI = new Promise((resolve) => {
        this.loadScript();
        resolve(true);
    });
}

public loadScript() {        
    var isFound = false;
    var scripts = document.getElementsByTagName("script")
    for (var i = 0; i < scripts.length; ++i) {
        if (scripts[i].getAttribute('src') != null && scripts[i].getAttribute('src').includes("loader")) {
            isFound = true;
        }
    }

    if (!isFound) {
        var dynamicScripts = ["https://widgets.skyscanner.net/widget-server/js/loader.js"];

        for (var i = 0; i < dynamicScripts.length; i++) {
            let node = document.createElement('script');
            node.src = dynamicScripts [i];
            node.type = 'text/javascript';
            node.async = false;
            node.charset = 'utf-8';
            document.getElementsByTagName('head')[0].appendChild(node);
        }

    }
}