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javascriptarraysreactjsslicesplice

React splice returns opposite of what I delete?

I am trying to delete first two, three, four indices of an array. This is my code:

 returnFilteredRoles() {
    if (this.props.user.role_id == 1 || this.props.user.role_id == 2) {
      return this.state.data;
    } else if (this.props.user.role_id == 3) {
      return this.state.data.splice(0, 2);
    } else if (this.props.user.role_id == 4) {
      return this.state.data.splice(0, 3);
    } else if (this.props.user.role_id == 5) {
      return this.state.data.splice(0, 4);
    }
  }

ex: data = [1,2,3,4,5]; if role_id == 3, it should return [3,4,5]. instead it returns [1,2]. no Idea why.

I tried storing the state into a variable and splicing that variable and returning that. But it gives same result.

Solution

  • The thing is, that slice returns the elements that you cut out:

    var fruits = ["Banana", "Orange", "Lemon", "Apple", "Mango"];
var citrus = fruits.slice(1, 3);
console.log(citrus); // ["Orange", "Lemon"]

    Source: https://www.w3schools.com/jsref/jsref_slice_array.asp