计算特定键

Question

我有这个对象：

"formData": {
    "Total": "60.00",
    "listTable": [],
    "tr0_CC": "KFC",
    "tr0_amount": "10.00",
    "tr1_CC": "SUB",
    "tr1_amount": "20.00",
    "tr2_CC": "WEN",
    "tr2_amount": "30.00"
}

如何只使用native或lodash计算键tr#_amount？在上面的例子中，我应该得到3。

Answer 1

这里有一些标准（ES6）Javascript：

＆＃13;

＆＃13;

a = {"formData": {
    "Total": "60.00",
    "listTable": [],
    "tr0_CC": "KFC",
    "tr0_amount": "10.00",
    "tr1_CC": "SUB",
    "tr1_amount": "20.00",
    "tr2_CC": "WEN",
    "tr2_amount": "30.00"
}};

console.log(Object.keys(a.formData).filter(t => t.match(/tr\d+_amount/)).length);

＆＃13;

＆＃13;

＆＃13;