I have been stumped by this looking for some direction. I have a state object:
const state = [
{type: 'Primary', number: 123456},
{type: 'Mobile', number: 789012}
]
I have a function which is giving me the updated values for the oldValue, newValue, and index.
How would I be able to replace the specific number value for example in the 'Mobile' object and return the new array?
If you have the state array index you need to change, the newValueand oldValue:
const newState = state.map((obj, i) => {
if(i === index && obj.number === oldValue) {
let newObj = { ...obj };
newObj.number = newValue;
return newObj;
}
return obj;
}
number, you can do everything in one step: return { ...obj, number: newValue };You can use array.find() to find the corresponding object and replace a specific value :
const state = [
{type: 'Primary', number: 123456},
{type: 'Mobile', number: 789012}
]
// This will find and return the FIRST item that matches, or undefined if none are found
const ObjectToChange = state.find(elem => elem.type === 'Mobile')
if (ObjectToChange != undefined)
ObjectToChange.number = 42;
console.log(state);If you mean change the value:
const state = [
{type: 'Primary', number: 123456},
{type: 'Mobile', number: 789012}
];
state[state.findIndex(item=>item.type==='Mobile')]={type:'Mobile',number:1111}
console.log(JSON.stringify(state,null,2));
const state = [
{type: 'Primary', number: 123456},
{type: 'Mobile', number: 789012}
]
const someFunction = (state, oldValue, newValue, index) => {
let newState = state.map(e => {
if(e.type === index) e.number = newValue;
return e
})
return newState
}
const newState = someFunction(state, '', 123456, 'Mobile')
console.log(newState)You could use Array.map to return the updated array like so:
const updateFunction = (state, oldValue, newValue, index) => {
return state.map((stateObject, i) => i === index ? ({ ...stateObj, number: newValue }) : stateObject);
}
state, using spread syntax,.splice()shallow copy by index inserting modified object and set state to modified arrayidproperty for each object and access those items byid.