SOURCE

function template(string, data) {
    var num = string.split("$").length - 1;
    var nStr = string;
    var newStr1 = [];
    var newStr2 = [];
    for (var i = 0; i < num; i++) {
        var a = nStr.indexOf("$")
        var b = nStr.indexOf("}")
        newStr1.push(nStr.slice(a, b + 1))
        newStr2.push(nStr.slice(a + 2, b));
        nStr = nStr.substr(b + 1)
    }
    for (var key in data) {
        for (var j = 0; j < newStr2.length; j++) {
            if (key == newStr2[j]) {
                string = string.replace(newStr1[j], data[key])
            }
        }
    }
    return string
}
console.log(template('您已购买${count}种共${amount}件商品，总价${totalPrice}元', {
    amount: 10,
    count: 3,
    totalPrice: 100
}))