Unresolved function when using method map()

Question

Unable to resolve function map(). I also tried importing rxjs/add/operator/map

getVenues() {
if (this.placeValue != null && this.placeValue != "" && this.recipeValue != null && this.recipeValue != "") {
  this._http.get("https://api.foursquare.com/v2/venues/search" +
    "?client_id=3PPNMTIKJJNDVYPFOBGSHHV2PR5A2P05PYHXDN2MKSKTTBSX" +
    "&client_secret=0QPHT0F5RS043F4TB4KKPQSHKSAXKE5ZNOYGB5KL2MBDYAG4" +
    "&v=20160215&limit=5" +
    "&near=" + this.placeValue +
    "&query=" + this.recipeValue)
    .map(res => res.json())
    .subscribe(data => {
      // we've got back the raw data, now generate the core schedule data
      // and save the data for later reference
      this.data1 = data.results[0].key;
      console.log(this.data1)},
      err => console.log(err)

      );

If I use HttpClientModule instead of HttpClient, I get the error

Unable to resolve method get()

Can you provide stackBlitz for this? or you can convert that in to promise also — Prashant Pimpale
– Prashant Pimpale, Commented Jan 19, 2019 at 5:42
Which version of Angular do you use? If its greater than 6 then wrap your map with a pipe method, or you don't have to manually convert to json as by default you will get parsed json only. — Anoop Mc
– Anoop Mc, Commented Jan 19, 2019 at 6:31

Hearen · Accepted Answer · 2019-01-19 06:25:40Z

1

Normally we use pipe() when using httpclient.

this.http.get(url).pipe(map(a => b), catchError(error => this.handleError(error)));

Just as its comments of httpClient.get():

/**
 * Construct a GET request which interprets the body as JSON and returns it.
 *
 * @return an `Observable` of the body as type `T`.
 */

Since it's returning an Obervable then you follow the pipe to merge the functions into a chain.

Tips

you should use !== and === in JS to avoid weird results;
normally we do not subscribe directly after the get and we put the get method in a separate service;

edited Jan 19, 2019 at 6:25

answered Jan 19, 2019 at 6:18

Hearen

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2 Comments

user9718365 Over a year ago

Got to know that HttpClient.get() applies res.json() automatically and returns Observable<HttpResponse<string>>. So, the map() can be removed. As said, if we donot subscribe() directly after get, when to do it?

Hearen Over a year ago

Move the get methods to a service and subscribe when used in the components, it’s easier to test and manage since the components shall not consider how to get the data actually.

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