In JSX, how do you reference a value from props
from inside a quoted attribute value?
For example:
React (or JSX) doesn't support variable interpolation inside an attribute value, but you can put any JS expression inside curly braces as the entire attribute value, so this works:
<img className="image" src={"images/" + this.props.image} />
Best practices are to add getter method for that :
getImageURI() {
return "images/" + this.props.image;
}
<img className="image" src={this.getImageURI()} />
Then , if you have more logic later on, you can maintain the code smoothly.
Instead of adding variables and strings, you can use the ES6 template strings! Here is an example:
<img className="image" src={`images/${this.props.image}`} />
As for all other JavaScript components inside JSX, use template strings inside of curly braces. To "inject" a variable use a dollar sign followed by curly braces containing the variable you would like to inject. For example:
{`string ${variable} another string`}
Note: In react you can put javascript expression inside curly bracket. We can use this property in this example.
Note: give one look to below example:
class LoginForm extends React.Component {
constructor(props) {
super(props);
this.state = {i:1};
}
handleClick() {
this.setState(prevState => ({i : prevState.i + 1}));
console.log(this.state.j);
}
render() {
return (
<div>
<p onClick={this.handleClick.bind(this)}>Click to change image</p>
<img src={'images/back'+ this.state.i+'.jpg'}/>
</div>
);
}
}
If you're using JSX with Harmony, you could do this:
<img className="image" src={`images/${this.props.image}`} />
Here you are writing the value of src
as an expression.
If you want to use the es6 template literals, you need braces around the tick marks as well:
<img className="image" src={`images/${this.props.image}`} />