How to load the script file immediately (dynamically added) before continue?

 you can return a promise to chain calls

export class HomeComponent {
    constructor() {
        this.loadDynmicallyScript()
        .then(() => {
          this.doSomethingWhenScriptIsLoaded();
        });
    } 
     public loadDynmicallyScript():Promise {
        var script = document.createElement('script');
        script.src = "../node_modules/xxxxxx/i18n/xx.min.js";
        script.async =false;
        document.head.appendChild(script);
        return Promise((resolve, reject) => {
          script.onload = resolve;
        });    
     }

or just pass a function to the onLoad to be called when the script was loaded

export class HomeComponent {
    constructor() {
        this.loadDynmicallyScript()
    } 
     public loadDynmicallyScript():Promise {
        var script = document.createElement('script');
        script.src = "../node_modules/xxxxxx/i18n/xx.min.js";
        script.async =false;
        document.head.appendChild(script);
        script.onload = () => this.doSomethingWhenScriptIsLoaded();
     }

Another one

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);
        }

    }
}