Javascript筛选器方法返回原始数组，即使返回false也是如此

我有一个过滤方法，如下所示：

    let newArray = Alerts[symbol].filter(async (alert: IDiscordSymbolAlert, alert_index: number) => {
        // If Price when set is greater than alert price, price has to move UP to trigger
        if (alert.price_when_set < alert.alert_price) {
            hasToGo = Change.UP;
        } 
        // If Price when set is greater than alert price, price has to move DOWN to trigger
        else if (alert.price_when_set > alert.alert_price){
            hasToGo = Change.DOWN;
        }

        /**If the hasToGo is UP and current price is greater than alert price, then ALERT USER [OR]
        // If the hasToGo is DOWN and current price is lesser than alert price, then ALERT USER **/ 
        if((hasToGo === Change.UP && (price >= alert.alert_price)) ||
        (hasToGo === Change.DOWN && (price <= alert.alert_price))) {
            /**
             * Send Notification that alert has been hit
             */
            let userToSend = await discord.users.fetch(alert.userID)
            if(!userToSend) return;
            //@ts-ignore
            userToSend.send(`> @everyone\n\n${symbol} has reached your alert price - ${alert.alert_price}`);
            // remove that alert
            guild_modified = true;
            return false;
        }

        return true;
    });


    // When logged here, it shows the entire array even though certain values have returned false.
    // I know they returned false because the block in which they returned false was executed and 
     //i did receive a notification which was executed in the same block.

    console.log(newArray);

因为过滤器在这种情况下不能与

async/await

一起使用。这是我使用

forEach（）

循环并使用

splice（）

手动删除数组中的匹配对象。但是因为forEach本身是异步的，并且

console.log

在异步块之外运行。它不会返回新数组，而是返回未修改的数组。如何返回要在forEach块范围之外使用的新数组

---

提前谢谢

您不能将

async

函数与

过滤器一起使用<代码>过滤器

返回回调函数返回真实值的所有元素

async

函数始终返回承诺，承诺是对象，所有非

null

对象都是真实的

如果您的

过滤器

检查需要是

异步的

，那么您的整个操作都是

异步的

，需要这样处理

这里有一个现成的

async

过滤函数，它并行执行元素检查。同样，与所有

async

函数一样，它返回一个结果承诺：

async function filterAsync(array, callback, thisArg = undefined) {
    const flags = await Promise.all(array.map(callback, thisArg));
    const result = [];
    for (let n = 0; n < array.length; ++n) {
        if (flags[n]) {
            result.push(array[n]);
        }
    }
    return result;
}

或

async function filterAsync(array, callback, thisArg = undefined) {
    const flags = await Promise.all(array.map(callback, thisArg));
    const result = [];
    for (let n = 0; n < array.length; ++n) {
        if (flags[n]) {
            result.push(array[n]);
        }
    }
    return result;
}

// In an `async` function (assuming you want errors to propagate):
const newArray = await filterAsync(Alerts[symbol], element => /*...keep-or-toss logic...*/);
// ...use `newArray`...

// Not in an `async` function
filterAsync(Alerts[symbol], element => /*...keep-or-toss logic...*/)
.then(newArray => {
    // ...use `newArray`...
})
.catch(error => {
    // ...handle/report error...
});