reactjs - Remove value from array in Reducer -
so have following code. if action active, itll store activity type in array called selectedactivitytype. however, trying remove activity type if action not active.
any ideas:
const initialuserstate = { selectedactivitytype: [], } export const activitytypes = (state = selectedactivitytype, action) => { switch (action.type) { case types.diary_update_activity_type: if(action.active) { return { ...state, selectedactivitytype: [...state.selectedactivitytype, action.activitytypeid], } } else { return { ...state, } } default: return state } }
i've taken code here , modified use in snippet examples.
the below snippet illustrate problem. current setup push value array if exists. meaning not have unique values in array. run snippet below , see duplicate entry.
let state = { selectedactivitytype: [ ] }; const activitytypes = (state = selectedactivitytype, action) => { switch (action.type) { case "update_activity_type": return { ...state, selectedactivitytype: [...state.selectedactivitytype, action.activitytypeid] } default: return state } } const addselectedactivitytype = (activitytypeid) => { return { type: "update_activity_type", activitytypeid } }; state = activitytypes(state, addselectedactivitytype("testid")); state = activitytypes(state, addselectedactivitytype("testid")); console.log(state);what can make helper function use in our reducer. if run below snippet see though tried add same value twice, end result 1 entry.
let state = { selectedactivitytype: [ ] }; const activitytypes = (state = selectedactivitytype, action) => { switch (action.type) { case "update_activity_type": if ( !existsinarray( state.selectedactivitytype, action.activitytypeid ) ) { return { ...state, selectedactivitytype: [...state.selectedactivitytype, action.activitytypeid] } } else { return state; } default: return state } } const addselectedactivitytype = (activitytypeid) => { return { type: "update_activity_type", activitytypeid } }; state = activitytypes(state, addselectedactivitytype("testid")); state = activitytypes(state, addselectedactivitytype("testid")); console.log(state); // helper function function existsinarray( array, value ) { let i; const length = array.length; ( = 0; < length; i++ ) { if ( array[ ] === value ) return true; } return false; }now know entries in array unique can remove entries array helper function. view below snippet gist!
let state = { selectedactivitytype: [ "testid", "anotherid" ] }; const activitytypes = (state = selectedactivitytype, action) => { switch (action.type) { case "remove_activity_type": removefromarray( state.selectedactivitytype, action.activitytypeid ); return state; default: return state } } const removeselectedactivitytype = (activitytypeid) => { return { type: "remove_activity_type", activitytypeid } }; console.log( state ); state = activitytypes(state, removeselectedactivitytype("testid")); console.log(state); // helper functions function existsinarray( array, value ) { let i; const length = array.length; ( = 0; < length; i++ ) { if ( array[ ] === value ) return true; } return false; } function removefromarray( array, value ) { let index = array.indexof( value ); if ( index > -1 ) { array.splice( index, 1 ); } }hope helps. ask questions if need to.
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