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Template literals are used in React for string interpolation, for example <div className={text-white ${myClass}}>. Template literals are delimited with backticks and allow us ${expression}to embed variables and expressions using the dollar sign and curly brace syntax.

import './App.css';

export default function App() {
  const myClass = 'bg-salmon';

  const name = 'James Doe';

  const num = 30;
  return (
    <div>
      <div className={`text-white ${myClass}`}>Some content here</div>

      <br />

      <div className={`text-white ${'hi'.length === 2 ? 'bg-salmon' : ''}`}>
        Some content here
      </div>

      <h2>Hello {name}</h2>

      <h2
        style={{
          padding: `${num + num}px`,
          backgroundColor: 'lime',
        }}
      >
        30 + 30 = {num + num}
      </h2>
    </div>
  );
}

Here is the CSS for the example.

App.css

.bg-salmon {
  background-color: salmon;
}

.text-white {
  color: white;
}

We can use template literals to insert variables in strings.

请注意, the string is enclosed in backticks `` instead of single quotes.

The dollar sign and curly brace syntax allows us to use placeholders that are evaluated.

<div className={`text-white ${myClass}`}>Some content here</div>

<div className={`text-white ${'hi'.length === 2 ? 'bg-salmon' : ''}`}>
  Some content here
</div>

The curly braces that we wrap the template literal in mark the beginning of the expression that must be evaluated.

The code between the opening and closing curly braces is just JavaScript, so any variables or expressions we use in the template literal will be evaluated.

When we JSXpresent a variable or expression in our code, we must wrap it in curly braces.

<h2>Hello {name}</h2>

We can also use template literals outside of JSX code.

const num = 50;

const result = `${num + 50} percent`;

console.log(result); // 👉️ 100 percent

By default, template literals concatenate the parts into a single string.

We can also use template literals to insert variables in multi-line strings.

const color1 = 'red';
const color2 = 'blue';

const poem = `roses are ${color1}
violets are ${color2}`;

console.log(poem);
// 👉️ roses are red
// 👉️ violets are blue

This is very useful as we don't have to add newlines on every line, instead when concatenating the strings.

We can even call functions in template literals.

import './App.css';

export default function App() {
  const subtract = (a, b) => {
    return a - b;
  };

  const myClass = 'bg-salmon';

  const num = 30;
  return (
    <div>
      <div
        style={{fontSize: `${subtract(60, 20)}px`}}
        className={`padding-${subtract(100, 80)} text-white ${myClass}`}
      >
        Some content here
      </div>
    </div>
  );
}

Here is an example of using the ternary operator with template literals.

const color1 = 'blue';
const color2 = 'red';

const result = `${color1.length > color2.length ? color1 : color2}`;

console.log(result); // 👉️ blue

The ternary operator is basically a _ if/elsestatement. The part before the question mark is evaluated, and if it returns a true value, the operator returns the value before the colon, otherwise it returns the value after the colon.

import './App.css';

export default function App() {
  return (
    <div>
      <div className={`text-white ${'hi'.length === 2 ? 'bg-salmon' : ''}`}>
        Some content here
      </div>
    </div>
  );
}

The ternary operator in the example checks whether the length of the string hi is equal to 2 and returns the string if it is, bg-salmonotherwise it returns an empty string.

||We can also use logical OR and logical AND &&operators in template literals .

const num1 = 0;
const num2 = 100;

const result = `${num1 || num2}`;
console.log(result); // 👉️ 100

The logical OR ||operator returns the value on the left side if it is true, otherwise it returns the value on the right side.

Following is an &&example of using the logical AND operator with template literals.

const bool = true;
const str = 'hello';

const result = `${bool && str}`;
console.log(result); // 👉️ hello

The logical AND &&operator returns the value to the left if it is false, otherwise it returns the value to the right.