I have a function that creates a long link. It does this by letting people click on multiple answers that belong to multiple question. Each question with it's answers belong to part of a multidimentional array.

Link creator:

        /**
         * Returns the parameters for the URL.
         *
         * @returns {string}
         */
        getLink() {
            let quizUrl = control.url[control.questionNumber];
            this.tmp = [];
            for (let i = 0; i < this.url.length; i  ) {
                // Check if question is from the same quiz part and adds a , between chosen answers and add the right prefix at the beginning
                if (this.url[i].length > 0) {
                    this.tmp.push(""   Quiz[i].prefix   this.url[i].join(","))
                    // console.log(this.url)
                }
                    if (this.url[i].length === 0) {
                        this.tmp.push("");
                }
                // console.log(quizUrl.length)
                console.log(this.tmp);
            }
            /// If answers are from different quiz parts add a & between answers.
            return ""   this.tmp.join("&");
        };

Array:

    class QuizPart {
        constructor(questionText, chosenAnswer, prefix, questionDescription) {
            this.questionText = questionText;
            this.chosenAnswer = chosenAnswer;
            this.prefix = prefix;
            this.questionDescription = questionDescription;
        }
    }

    class ChosenAnswer {
        constructor(id, name) {
            this.id = id;
            this.name = name;
        }
    }

    let Quiz = [
        new QuizPart('Whats your size?', [
                new ChosenAnswer('6595', '41'),
                new ChosenAnswer('6598', '42'),
                new ChosenAnswer('6601', '43'),
                new ChosenAnswer('', ''),
            ], 'bd_shoe_size_ids=',
            'The size of your shoes is very important. If you have the wrong size, they wont fit.'),

        new QuizPart('What color would you like?', [
                new ChosenAnswer('6053', 'Red'),
                new ChosenAnswer('6044', 'Blue'),
                new ChosenAnswer('6056', 'Yellow'),
                new ChosenAnswer('6048', 'Green'),
                new ChosenAnswer('', ''),
            ], 'color_ids=',
            'Color isn t that important, It looks good tho.'),

        new QuizPart('What brand would you like?', [
                new ChosenAnswer('5805', 'Adidas'),
                new ChosenAnswer('5866', 'Nike'),
                new ChosenAnswer('5875', 'Puma'),
                new ChosenAnswer('', ''),
            ], 'manufacturer_ids=',
            'Brand is less important. Its just your own preference'),
    ]

Everytime you go over to a new question in getLink() it joins the 2 questions with an &. When you console log getLink() it looks like this:

bd_shoe_size_ids=6595&color_ids=6044&manufacturer_ids=5875,5866

But uif you skip a question it adds the & sign anyway. So if is skip the first question there's an & sign at the beginning. If i skip the second it adds 2 in the middel like this:

bd_shoe_size_ids=6595&&manufacturer_ids=5875

And if you skip the last one it adds on at the end.

I tried using replace to replace two & signs with only one and delete them if they are at the very beginning or end, but it doesn't work. Does anybody know a good way to not join them if no value is in the string?

CodePudding user response：

replace only works on the first found item in the string. You can either use replaceAll, or split and join, which is more cross-browser friendly as below:

function cleanLink(link) {
  let newLink = link.split('&&').join('&'); // remove duplicate ampersands
  if (newLink[0] === '&') {
    newLink = newLink.slice(1); // remove starting ampersand
  }
  if (newLink[newLink.length - 1] === '&') {
    newLink = newLink.slice(0,-1); // remove trailing ampersand
  }
  return newLink;
}