Concatenating variables and strings in React

Question

Is there a way to incorporate React's curly brace notation and an href tag? Say we have the following value in the state:

{this.state.id}

and the following HTML attributes on a tag:

href="#demo1"
id="demo1"

Is there a way I can add the id state to the HTML attribute to get something like this:

href={"#demo + {this.state.id}"}

Which will yield:

#demo1

Answer 1

You're almost correct, just misplaced a few quotes. Wrapping the whole thing in regular quotes will literally give you the string #demo + {this.state.id} - you need to indicate which are variables and which are string literals. Since anything inside {} is an inline JSX expression , you can do:

href={"#demo" + this.state.id}

This will use the string literal #demo and concatenate it to the value of this.state.id . This can then be applied to all strings. Consider this:

var text = "world";

And this:

{"Hello " + text + " Andrew"}

This will yield:

Hello world Andrew 

You can also use ES6 string interpolation/ template literals with ` (backticks) and ${expr} (interpolated expression), which is closer to what you seem to be trying to do:

href={`#demo${this.state.id}`}

This will basically substitute the value of this.state.id , concatenating it to #demo . It is equivalent to doing: "#demo" + this.state.id .

Answer 2

the best way to concat props/variables:

var sample = "test";    
var result = `this is just a ${sample}`;    
//this is just a test

Answer 3

你可以简单地做到这一点..

 <img src={"http://img.example.com/test/" + this.props.url +"/1.jpg"}/>

Answer 4

用于在 React 中使用 map 连接变量和字符串，例如：

{listOfCategories.map((Categories, key) => { return ( <a href={`#${Categories.designation}`} className="cat-link" key={key}> </div> </a> ); })}

Answer 5

If u want to do it in JSX

<button className={`tab__btn first ${props.state}`} >
    {props.text}
</button>

Answer 6

Is there a way to incorporate React's curly brace notation and an href tag? Say we have the following value in the state:

{this.state.id}

and the following HTML attributes on a tag:

href="#demo1"
id="demo1"

Is there a way I can add the id state to the HTML attribute to get something like this:

href={"#demo + {this.state.id}"}

Which will yield:

#demo1