How can I assign a multiline string literal to a variable in JavaScript?

To assign a multiline string literal to a variable in JavaScript, you can use template literals (enclosed with backticks `), which support multiline strings without special formatting. Here are the methods and considerations:

1. Using Template Literals (ES6+)

Template literals preserve line breaks and indentation exactly as written:

const multilineStr = `This is a
multiline string
using backticks.`;

console.log(multilineStr);
// Output:
// This is a
// multiline string
// using backticks.

2. Handling Indentation

To avoid unwanted leading/trailing whitespace:

const cleanStr = `
  This line has no leading spaces.
    This line is indented in the string.
`.trim(); // Removes leading/trailing whitespace

console.log(cleanStr);
// Output:
// This line has no leading spaces.
//   This line is indented in the string.

3. Legacy Approach (Pre-ES6)

For environments that don’t support ES6, use string concatenation with + and \n:

var oldMultilineStr = "This is a\n" +
                     "multiline string\n" +
                     "using concatenation.";

4. Escaping Backticks

Include backticks in the string by escaping them with \:

const withBacktick = `This string contains a \` backtick.`;

Key Notes

• Whitespace: Indentation in the code becomes part of the string. Use .trim() to remove leading/trailing spaces.
• Browser Support: Template literals work in modern browsers (ES6+) but not in IE.
• Readability: Template literals are cleaner than concatenation for multiline text.

Example with Dynamic Content

Template literals also support embedded expressions (${...}):

const user = "Alice";
const message = `Hello ${user},
Your account balance is $100.
Thank you!`;

console.log(message);
// Output:
// Hello Alice,
// Your account balance is $100.
// Thank you!

Summary

Method	Example	Use Case
Template Literals	`Line 1\nLine 2`	Modern code, readability, dynamic content
String Concatenation	"Line 1\n" + "Line 2"	Legacy environments
.trim()	\n Text\n.trim()	Remove leading/trailing whitespace

Preferred Method: Use template literals for clarity and ease.