CODEWITHSUNDEEP
ecmascript-6superagentes6-promise
rross
rross

Reputation: 2276

Promises es6 and superagent

I'm attempting to use es6 promises with superagent. I'm attempting to call a function that has a superagent request wrapped inside. 

Request.post(buildReq).then(res => {
 if (res.ok) {//process res}
});

Here is the function wrapping superagent

  static post(params) {
    superagent
      .post(params.url)
      .send(params.payload)
      .set('Accept', 'application/json')
      .end((error, res) => {
        return this.Promise.resolve(res);
      })
      .bind(this);
  }

I'm getting an error

enter code here Uncaught TypeError: Cannot read property 'then' of undefined

When I change the return of the function to 

static post(params) {
    return Promise.resolve(superagent
      .post(params.url)
      .auth(params.auth.username, params.auth.password)
      .send(params.payload)
      .set('Accept', 'application/json')
      .end((error, res) => {
        return this.Promise.resolve(res);
      })
    );
  }

It looks like the data is returned in my browser's dev tools, but I cannot get to it within the .then function. How can I get the response from the promise.

Upvotes: 11

Views: 13549

Answers (5)

Arnaud M.
Arnaud M.

Reputation: 149

As of v2.0.0, superagent provides an ES6-compatible .then(). So your code could become 

static post(params) {
return superagent
        .post(params.url)
        .auth(params.auth.username, params.auth.password)
        .send(params.payload)
        .set('Accept', 'application/json')
        .then((res) => {
            return res;
        });
}

Upvotes: 2

Brent Washburne
Brent Washburne

Reputation: 13158

With ES6, you can use async/await with Promise and Generator support:

const res = await request.get(url);

Upvotes: -1

jsdario
jsdario

Reputation: 6853

Sometimes you'd like to avoid an indentation level caused by new Promise(...) then you can use directly Promise.reject and Promise.resolve.

static post(params) {
    return superagent
            .post(params.url)
            .auth(params.auth.username, params.auth.password)
            .send(params.payload)
            .set('Accept', 'application/json')
            .end((error, res) => {
                return error ? Promise.reject(error) : Promise.resolve(res);
            });
    });
}

Upvotes: 6

Cristian Sima
Cristian Sima

Reputation: 11

This is a more consise version, in case you need it for a lot of requests

import request from "superagent";

const withPromiseCallback = (resolve, reject) => (error, response) => {
  if (error) {
    reject({error});
  } else {
    resolve(response.body);
  }
};

export const fetchSuggestions = (search) => new Promise((resolve, reject) =>
 request.
    get("/api/auth/get-companies/0/50").
    type("form").
    set("Accept", "application/json").
    query({
      search,
    }).
    end(withPromiseCallback(resolve, reject))
);

export const fetchInitialInformation = () => new Promise((resolve, reject) =>
  request.
    get("/api/auth/check").
    set("Accept", "application/json").
    end(withPromiseCallback(resolve, reject))
);

Upvotes: 1

alexpods
alexpods

Reputation: 48505

It doesn't matter what you're returning from the end method callback, as it asynchronously executed when you've get response and result of callback execution is nowhere used. Look here and here in the source code. end method returns this, so in your second example you're resolving superagent not response. To get response your post method must looks like:

static post(params) {
    return new Promise((resolve, reject) => {
        superagent
            .post(params.url)
            .auth(params.auth.username, params.auth.password)
            .send(params.payload)
            .set('Accept', 'application/json')
            .end((error, res) => {
                error ? reject(error) : resolve(res);
            });
    });
}

Upvotes: 29

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