javascript - Q.all 用于非 promise 和 promise 组合

Question

我在做什么:我接受一个 svn url 数组，然后对所有 url 执行 checkout 操作。

问题:当被调用的函数不返回 promise 时，我无法使 Q.all 失败。

注意:使用 Q版本2.x

源代码:

const SvnSpawn = require("svn-spawn");
const Q = require("q");
const validations = require("./validations.js");
const client = new SvnSpawn();

/**
 * Silently checkout the svn content to the specified folder
 * @param {String} svnUrl - URL for the svn checkout
 * @param {String} destPath - Path to the destination folder
 * @returns {void}
 * @private
 */
function checkout(svnUrl, destPath){
    if(validations.isValidString(svnUrl) && validations.isValidString(destPath)){
        const deferred = Q.defer();

        client.cmd(["export", "--force", "--quiet", svnUrl, destPath], (err) => {
            if(err){
                deferred.reject(err);
            }
            else{
                deferred.resolve();
            }
        });
        return deferred.promise;
    }
    else{
        return new Error("SVN: svn url or destination path are not valid");
    }
}

/**
 * Checkout all the svn dependencies
 * @param {String[]} svnDependencies - Collection of SVN dependencies
 * @param {String} workingFolder - Path to the working folder
 * @returns {void}
 * @public
 */
function svnCheckout(svnDependencies, workingFolder){
    const deferred = Q.defer();

    Q.all(svnDependencies.map((svnUrl) =>
            checkout(svnUrl, workingFolder)
        ))
        .then((response) => {
            deferred.resolve();
        })
        .catch((err) => {
            deferred.reject(err);
        });

    return deferred.promise;
}

module.exports.checkout = svnCheckout;

上面的代码是如何使用的:

const svn = require("./lib/util/svnOperations");

svn.checkout([
    1,
    "http://<url>",
    "http://<url>"
], "./working")
.then(() => {
    console.log("Done");
})
.catch((err) => {
    console.error(err);
})
.done();

预期:上面的代码应该会导致错误，但会以 Done 退出。

Answer 1

让您的代码在失败时返回拒绝的 promise ，

return Q.reject(new Error("SVN: svn url or destination path are not valid"));