84 lines
2.1 KiB
Markdown
84 lines
2.1 KiB
Markdown
---
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title: State vs Props
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---
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## State vs Props
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When we start working with React components, we frequently hear two terms. These are `state` and `props`. So, in this article we will explore what those are and how they differ.
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## State:
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* State is something that a component owns. It belongs to that particular component where it is defined.
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For example, A person's age is a state of that person.
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* State is mutable. But it can only be changed by the component itself, meaning it is private. As I only can change my age, no one else can.
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* You can change the state by using `this.setState()`
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See the below example to get an idea of state:
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#### Person.js
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```javascript
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import React from 'react';
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class Person extends React.Component{
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constructor(props) {
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super(props);
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this.state = {
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age:0
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this.incrementAge = this.incrementAge.bind(this)
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}
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incrementAge(){
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this.setState({
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age:this.state.age + 1;
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});
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}
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render(){
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return(
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<div>
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<label>My age is: {this.state.age}</label>
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<button onClick={this.incrementAge}>Grow me older !!</button>
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</div>
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);
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}
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}
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export default Person;
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```
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In the above example, `age` is the state of `Person` component.
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## Props:
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* Props are similar to method arguments. They are passed to a component when it is instantiated.
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* Props are immutable. They are read-only.
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See the below example to get an idea of Props:
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#### Person.js
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```javascript
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import React from 'react';
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class Person extends React.Component{
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render(){
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return(
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<div>
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<label>I am a {this.props.character} person.</label>
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</div>
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);
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}
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}
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export default Person;
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const person = <Person character = "good"></Person>
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```
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In the above example, `const person = <Person character = "good"></Person>` we are passing `character = "good"` prop to `Person` component.
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It gives output as "I am a good person", in fact I am.
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There is lot more to learn on State and Props. Many things can be learnt by actually diving into coding. So get your hands dirty by coding.
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Happy Coding !!!
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