Question

129

Javascript - How to use promises with multiple .then()

rated 0 times [ 134] [ 5] / answers: 1 / hits: 45620 / 7 Years ago, thu, march 30, 2017, 12:00:00

I'm trying to create a array structure. So, we have parts and each part had articles.

So i did a promise to collect all parts .then() i need to iterate part promise and select the articles in this part .then() i want to push this to a array parts and render this in a view.

The structure is this:

-PARTS

      - part

            - u_order

            - u_familia

            - u_part

            - u_type

            - articles (article from each part)

And my code is this:

var p1 = new Promise(function(resolve, reject) {

      var stamp = req.params.stamp;

      request.query(SELECT u_order, u_familia, u_part, u_type FROM u_part (nolock) where u_order <'92' and u_order <> '100').then((data)=>resolve(data));

      // or

      // reject (Error!);

    });







    p1.then(function(value){

      var stamp = req.params.stamp;

      console.log(value.length);

      for(var i= 0; i<value.length; i++)

      {

        console.log(value[i]);

        request.query(SELECT st.u_posic, sc.ref, sc.qtt, sc.design FROM st INNER JOIN sc ON st.ref = sc.ref where sc.ststamp ='+stamp+' and st.u_posic = '+value[i].u_order+').then((data)=>resolve(data));

      }



    }, function(reason){

      console.log(reason);

    });



    p1.then(function(part, articles){

      var parts = [];

      console.log(PART:  +part.length);

      for(var j= 0; j<part.length; j++)

      {

        console.log(part[j].u_order);

        console.log(part[j].u_familia);

        console.log(part[j].u_part);

        console.log(part[j].u_type);

        console.log(articles[j]);

      };

    });

In last .then() i just have the parts, i can't access to articles maybe because i'm not doing well with second .then()
I'm starting working with promises, i also read documentation but i can't do this.

Anyone can help me to understand and solve this?

Thank you

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

travion

Add To Favorites

Follow

Total Points: 137

Total Questions: 96

Total Answers: 103

Location: India

Member since Wed, Aug 4, 2021

3 Years ago

travion questions

1 Tagify set data in tagify input on click

Mon, Dec 16, 19, 00:00, 5 Years ago

1 Laravel - How to Import Vue Component to Another Component

Sat, Oct 19, 19, 00:00, 5 Years ago

1 Date conversion in react js

Fri, Sep 20, 19, 00:00, 5 Years ago

1 How can I style react semantic components?

Wed, Nov 14, 18, 00:00, 6 Years ago

1 Problem with onChange for Masked Input in React

Sun, Oct 28, 18, 00:00, 6 Years ago

View All

answered 7 Years ago jaelyn · Accepted Answer

The best I can do - I'll add explanation a little later (sorry, have to go)

request.query(SELECT u_order, u_familia, u_part, u_type FROM u_part (nolock) where u_order <'92' and u_order <> '100')

.then(function(parts){

    var stamp = req.params.stamp;

    return Promise.all(parts.map(function(part) {

        return request.query(SELECT st.u_posic, sc.ref, sc.qtt, sc.design FROM st INNER JOIN sc ON st.ref = sc.ref where sc.ststamp ='+stamp+' and st.u_posic = '+part.u_order+')

        .then(function(articles) {

            part.articles = articles;

            return part;

        });

    }));

})

.then(function(parts){

    parts.forEach(function(part) {

        console.log(part.u_order);

        console.log(part.u_familia);

        console.log(part.u_part);

        console.log(part.u_type);

        part.articles.forEach(function(article) {

            console.log(article.u_posic);

            console.log(article.ref);

            console.log(article.qtt);

            console.log(article.design);

        });

    });

});

BONUS ES2015+ version of above

request.query(SELECT u_order, u_familia, u_part, u_type FROM u_part (nolock) where u_order <'92' and u_order <> '100')

.then(parts => Promise.all(parts.map(part => request.query(`SELECT st.u_posic, sc.ref, sc.qtt, sc.design FROM st INNER JOIN sc ON st.ref = sc.ref where sc.ststamp ='${req.params.stamp}' and st.u_posic = '${part.u_order}'`)

    .then(articles => {

        part.articles = articles;

        return part;

    })

)))

.then(parts => parts.forEach(part => {

    console.log(part.u_order);

    console.log(part.u_familia);

    console.log(part.u_part);

    console.log(part.u_type);

    part.articles.forEach(article => {

        console.log(article.u_posic);

        console.log(article.ref);

        console.log(article.qtt);

        console.log(article.design);

    });

}));