从循环函数返回值

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这个 Meteor 服务器递归方法 commonHint 返回 result undefined 到控制台，即使 finalRes 有一个值.关于如何将 finalRes 返回给调用者的任何建议?谢谢

This Meteor server recursive method commonHint returns result undefined to the console even the finalRes has a value. Any suggestion on how to return the finalRes to the caller? thx

//call the recursive method let result = thismonHint(myCollection.findOne({age: 44}), shortMatches); console.log('got most common hint: ' + result); // <=== undefined ==== 'commonHint': function (doc, shortMatches, hinters, results = []) { // first call only first 2 args are defined, if (!hinters) { hinters = [...lib.getCombinations(['arg1', 'arg2', 'arg3'], 2, 3)]; thismonHint(doc, shortMatches, hinters, results); // hinters is an array of length 3 with 2 elements each return; } // get an element from hinters, use its 2 hinters and remove that element from the hinters let hintersToUse = hinters.pop(); let hinter1 = this.cleanMatchItem(hintersToUse[0]); let hinter2 = this.cleanMatchItem(hintersToUse[1]); let intersect = _.intersection(hinter1, hinter2); // which item of the shortMatches best matches with the intersect let tempCol = new Meteor.Collection(); for (let i = 0; i < shortMatches.length; i++) { tempCol.insert({match: shortMatches[i]}); } results.push(mostSimilarString(tempCol.find({}), 'match', intersect.join(' '))); if (hinters.length > 0) { thismonHint(doc, shortMatches, hinters, results); } else { let finalRes = lib.mostCommon(results); console.log(finalRes); //<==== has a value return finalRes; //<==== so return it to caller } },

推荐答案

递归函数中返回结果的每个路径必须返回一个结果.在您的路径中，您有不提供的路径:当未提供 hinters 时，以及当 hinters.length >0 为真.

Every path out of a recursive function that returns a result must return a result. In yours, you have paths that don't: When hinters isn't provided, and when hinters.length > 0 is true.

你应该返回递归调用的结果:

You should return the result of the recursive call:

if (!hinters) { hinters = [...lib.getCombinations(['arg1', 'arg2', 'arg3'], 2, 3)]; return thismonHint(doc, shortMatches, hinters, results); // hinters is an array of length 3 with 2 elements each // ^^^^^^ } // ... if (hinters.length > 0) { return thismonHint(doc, shortMatches, hinters, results); // ^^^^^^ } else { let finalRes = lib.mostCommon(results); console.log(finalRes); //<==== has a value return finalRes; //<==== so return it to caller }