RxJs move array of objects to root array

问题

I am getting below set of data via Observable

[
  0: {id: "12321", itemName: "Item 1", category: "All"},
  1: [
    0: {id: "423423", itemName: "Sub Item 1", category: "subcat"},
    1: {id: "413212", itemName: "Sub Item 2", category: "subcat"}
  ],
  2: {id: "65655", itemName: "Item 2", category: "All"},
  3: {id: "87877", itemName: "Item 3", category: "All"},
  4: [
    0: {id: "354345", itemName: "Sub Item 1", category: "subcat"},
    1: {id: "123434", itemName: "Sub Item 2", category: "subcat"},
    2: {id: "765767", itemName: "Sub Item 3", category: "subcat"},
    3: {id: "854643", itemName: "Sub Item 4", category: "subcat"},
  ]
]

I am trying to move all the objects within array to root array. The expected result is

[
  0: {id: "12321", itemName: "Item 1", category: "All"},
  1: {id: "423423", itemName: "Sub Item 1", category: "subcat"},
  2: {id: "413212", itemName: "Sub Item 2", category: "subcat"}
  3: {id: "65655", itemName: "Item 2", category: "All"},
  4: {id: "87877", itemName: "Item 3", category: "All"},
  5: {id: "354345", itemName: "Sub Item 1", category: "subcat"},
  6: {id: "123434", itemName: "Sub Item 2", category: "subcat"},
  7: {id: "765767", itemName: "Sub Item 3", category: "subcat"},
  8: {id: "854643", itemName: "Sub Item 4", category: "subcat"},
]

This is how the data looks on console

Below is what I've and tried so far.

lstCategories: Observable<any>;

this.lstCategories = .....
               .flatMap(records => Observable.combineLatest(records))
               .map(da => {
                  return da.map(mda => {
                     //if it is array then map each object in array.
                     if(mda.length){
                        return mda.map(smda => {
                           return Observable.of(smda);
                        })
                     }else {
                        return mda;
                     }
                  })
               });

console.log(da) i.e. first map displays the type of data I am getting. I am checking length of each element in array and mapping it back.

What is that I am missing here?

回答1:

Based on the image, you have an array of objects and array. You can flatten it using [].concat(...data). Use array#concat with spread syntax.

var data = [{id: "12321", itemName: "Item 1", category: "All"}, [{id: "423423", itemName: "Sub Item 1", category: "subcat"}, {id: "413212", itemName: "Sub Item 2", category: "subcat"}],{id: "65655", itemName: "Item 2", category: "All"}, {id:"87877", itemName: "Item 3", category: "All"}, [{id: "354345", itemName: "Sub Item 1", category: "subcat"}, {id: "123434", itemName: "Sub Item 2", category: "subcat"}, {id: "765767", itemName: "Sub Item 3", category: "subcat"}, {id: "854643",itemName: "Sub Item 4", category: "subcat"}]],
    result = [].concat(...data);
console.log(result);

来源：https://stackoverflow.com/questions/49407067/rxjs-move-array-of-objects-to-root-array

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