How to change a Item value of a state.

[Symous]

for example, I have a list state like this:

this.state = {
    list:[1,2,3,4,5]
}

How can I change the value of the first item of list from 1 to 0?

I usually use like this but I don't believe that is the best way.

var temp = this.state.list;
temp[0] = 0;
this.setState({ list : temp});

Please who can tell me is there any better way to do this ?

[HofmannZ]

You could use the immutability-helper, that would look something like this:

You have the following state, and want to change the first item in the list array.

this.state = {
  list: [1, 2, 3, 4, 5],
};

Using the update function, you can do the following:

import update from 'immutability-helper';

this.setState({
  list: update(this.state.list, {
    indexYouEdit: {
      $splice: [[indexYouEdit, amountOfRemoval, newValue, ...optionalNewValues]]
    },
  }),
});

Hope that helps you out!

[Symous]

@HofmannZ ,Thanks for your help.But when I import update from 'immutability-helper' to my page, there is a error said that -

Unable to resolve module 'immutability-helper' rom [MY_DIRECTORY];Modules does not exist in the module map or in theres directories ....

do you have any idea about this ?
PS: React Native 0.43 + Android ;

[HofmannZ]

Like any other package, you have to install it, depending on whether you use npm or yarn you would do one of the following:

npm
Navigate to the root of your react-native project, then run:
npm install --save immutability-helper

yarn
Navigate to the root of your react-native project, then run:
yarn add immutability-helper

This will add the package to your project.

[Symous]

@HofmannZ ,I simply consider that was intergered into react-native already. :-) . And can you tell me is there any other way without importing a third-party lib to achieve this ? Will be grateful to solve my confusion.Thanks again!