如何将Array.prototype.some()与异步函数一起使用? [英] How to use Array.prototype.some() with an async function?

问题描述

我正在尝试执行以下操作:

I am trying to do the following:

command.permissions.some(async permissionsKey => {
        switch (permissionsKey) {
            case "all": {
                return true;
            }
            case "OWNER": {
                return await msg.roomContext.isRoomOwnerId(msg.getStaticUserUID());
            }
            default: {
                return config.users_groups[permissionsKey].includes(msg.getStaticUserUID());
            }
        }
    });

但是它始终是正确的，因为Array.prototype.some不期望异步函数，因此在调用该函数时会返回一个promise.一个承诺是真实的.

However it always is true because Array.prototype.some does not expect an async function so a promise is returned when the function is called. A Promise is truthy.

我想知道将异步函数与Array.prototype函数(尤其是some函数)一起使用的最佳途径.

I was wondering the best away to use an async function with any of the Array.prototype functions, specifically the some function.

推荐答案

如果您希望在第一个承诺通过true解析后立即得到结果，您也可以这样做:

If you want the result as soon as the first promise resolves with true, you can do that too:

const somePromise = promises =>
    new Promise((resolve, reject) => {
        let resolveCount = 0;
        const resolved = value => {
            if (value) {
                resolve(true);
            } else if (++resolveCount === promises.length) {
                resolve(false);
            }
        };

        for (const promise of promises) {
            promise.then(resolved, reject);
        }
    });

其他花哨的方法:

const never = new Promise(() => {});

const somePromise = promises => Promise.race([
    Promise.race(promises.map(async p => !!await p || never)),
    Promise.all(promises).then(r => r.some(Boolean)),
]);

不过，在您的特定情况下，由于最多只有一个承诺，因此有更好的方法来实现:

In your specific case, though, since there’s at most one promise, there’s a much better way to do it:

let hasPermission =
    command.permissions.some(permissionsKey => {
        switch (permissionsKey) {
            case "all":
                return true;
            case "OWNER":
                return false;
            default:
                return config.users_groups[permissionsKey].includes(msg.getStaticUserUID());
        }
    });

if (!hasPermission && command.permissions.includes("OWNER")) {
    hasPermission = await msg.roomContext.isRoomOwnerId(msg.getStaticUserUID());
}

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