Q.all为非承诺和承诺组合

Question

What Am I Doing: I take in an array of svn url and then I perform a checkout operation on all the url.

Problem: I am not able to fail the Q.all when the called function doesn't return a promise.

Note: Using Q version 2.x

Source Code:

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;

How the above code is consumed:

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

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

Expectation: The above code should result in an error but it exits with Done .

Answer 1

让您的代码在失败时返回拒绝的承诺，

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