I've been trying to do the same, and as far as I can tell, you can't.
So, the developer of Walton (Walmart stock lookup app) shared a bit of his code
this.walmart.dotcom.query.URL1 = 'http://mobile.walmart.com/m/j?e=1&version=2&service=Browse&method=searchByDepartmentFiltered&p1=';
this.walmart.dotcom.query.URL2 = '&p2=ENTIRESITE&p3=All&p4=RELEVANCE&p5=';
this.walmart.dotcom.query.URL3 = '&p6=50&p7=%5B%5D';
this.walmart.dotcom.upcq = 'http://www.walmart.com/product/mobile/api/upc/';
this.walmart.dotcom.item = 'http://www.walmart.com/product/mobile/api/';
this.walmart.store.query = 'http://search.mobile.walmart.com/search?query=';
this.walmart.store.items = 'http://search.mobile.walmart.com/items';
getWalmartDotcomQuery(query){
return this.http.get(this.walmart.dotcom.query.URL1 + query + this.walmart.dotcom.query.URL2 + '0' + this.walmart.dotcom.query.URL3).map(res => res.json()); } getWalmartDotcomQueryMore(query, more){
return this.http.get(this.walmart.dotcom.query.URL1 + query + this.walmart.dotcom.query.URL2 + more + this.walmart.dotcom.query.URL3).map(res => res.json()); } getWalmartDotcomUPC(upc){
return this.http.get(this.walmart.dotcom.upcq + upc).map(res => res.json()); } getWalmartDotcomID(id){
return this.http.get(this.walmart.dotcom.item + id).map(res => res.json()); }getWalmartStoreQuery(query, offset){
return this.http.get('http://search.mobile.walmart.com/search?query='+query+'&store='+this.storeid+'&size=20&offset='+ offset).map(res => res.json()); }
Looks like we have to cross reference it from their official website as well.
Source:
https://www.reddit.com/r/walmart/comments/4hsq7s/questions_about_walmart_api/d2ste4f/