JavaScript - Expand variables in string

expandVars.js

// Polyfill to expand variables in a string

// Example: expandEnv("Welcome back ${name}. Glad to see you");
// Example: expandEnv("Welcome back $name. Glad to see you");
// eslint-disable-next-line no-extend-native
function expandEnv(s: string): string {
	return s.replace(/\$([\w]+|{([^{}]*)})/g, (str, varName) => {
		const vName = varName.startsWith("{") ? varName.substring(1, varName.length - 1) : varName;
		var value = process.env[vName];

		return typeof value === "string" || typeof value === "number" ? value : str;
	});
}