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JavaScript Build a REST API With Express Completing and Testing the API Test Routes with Postman

mulgey
mulgey
9,899 Points
Posted by mulgey
mulgey
9,899 Points

How does the "sorting" works here?

We have a questionSchema:

const QuestionSchema = new Schema({
    text: String,
    createdAt: {type: Date, default: Date.now},
    answers: [AnswerSchema]
});

And above the Schema, we have our sorting funct:

const sortAnswers = function (a,b) {
    if (a.votes === b.votes) {
        return b.updatedAt - a.updatedAt;
    }
    return b.votes - a.votes;
}

And lastly after these two, we've placed our pre save:

QuestionSchema.pre("save", function(next) {
    this.answers.sort(sortAnswers);
    next();
});

Watching this line of communication, i have difficulty to understand the logic behind the sortAnswers function.

1) In PostMan, or real-world-setting, when we vote up, how does it know to compare A and B, which becomes A and which becomes B?

2) And how the result (negative, 0, positive) affects the sorting? May you provide any documentation link about this?

Kind regards Mustafa

1 Answer

Putra Aryotama
Putra Aryotama
36,050 Points
Putra Aryotama
Putra Aryotama
36,050 Points

https://stackoverflow.com/questions/6567941/how-does-sort-function-work-in-javascript-along-with-compare-function/6568100

This is the best answer i can find.

Here's another resource from MDN docs. Scroll down to where they explain about "compare function": https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort