NativeScript/nativescript-core/globals/ts-helpers.ts

// Required by V8 snapshot generator
if (!global.__extends) {
	global.__extends = function (d, b) {
		for (let p in b) {
			if (b.hasOwnProperty(p)) {
				d[p] = b[p];
			}
		}
		function __() {
			this.constructor = d;
		}
		d.prototype =
			b === null
				? Object.create(b)
				: ((__.prototype = b.prototype), new __());
	};
}

import * as tslib from "tslib";

// Bind the tslib helpers to global scope.
// This is needed when we don't use importHelpers, which
// breaks extending native-classes
for (const fnName of Object.keys(tslib)) {
	if (typeof tslib[fnName] !== "function") {
		continue;
	}

	if (fnName in global) {
		// Don't override globals that are already defined (ex. __extends)
		continue;
	}

	global[fnName] = tslib[fnName];
}