Find and replace double curly braces in JavaScript, example: findReplace("Hello, {{ name }}", "name", "John"); // "Hello, John"

findReplace.js

/**
 * Format double braced template string 
 * @param {string} string
 * @param {string} find 
 * @param {string} replace
 * @returns {string}
 */
function Maparameter(string, find, replace) 
{
    if ((/[a-zA-Z\_]+/g).test(string)) {
        return string.replace(new RegExp('\{\{(?:\\s+)?(' + find + ')(?:\\s+)?\}\}'), replace);
    } else {
        throw new Error("Find statement does not match regular expression: /[a-zA-Z\_]+/");
    }
}

Maparameter("{{CustomerGuid}}", "CustomerGuid", "1234-4567-7891-1234");