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Strings & Templates

Q: What is the difference between single, double, and backtick quotes?

Answer: Single and double quotes are mostly identical for defining simple strings. Backticks (template literals) allow for multi-line strings, string interpolation using ${}, and including both single and double quotes without needing escape characters..

Q: How do you find the number of characters in a string?

Answer: You use the .length property on any string variable (e.g., myString.length)..

Q: What is an escape character?

Answer: An escape character (\) is used to tell JavaScript that a special character (like a quote or backslash) should be treated as literal text instead of a part of the language syntax..

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Expert Answer & Key Takeaways

Mastering Strings & Templates is essential for high-fidelity technical architecture and senior engineering roles in 2026.

JavaScript Strings

A JavaScript string is zero or more characters written inside quotes. Strings are used for storing and manipulating text.

1. Quotes and Strings

A JavaScript string can be written with single or double quotes:

let carName1 = "Volvo XC60";
let carName2 = 'Volvo XC60';

You can use quotes inside a string, as long as they don't match the quotes surrounding the string:

let answer1 = "It's alright";
let answer2 = "He is called 'Johnny'";
let answer3 = 'He is called "Johnny"';

2. String Length

To find the length of a string, use the built-in length property:

let text = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
let length = text.length;

3. Escape Characters

Because strings must be written within quotes, JavaScript will misunderstand this string:

// This will error
let res = "We are the so-called "Vikings" from the north.";

To solve this problem, you can use the backslash escape character. The backslash (\) escape character turns special characters into string characters:

Code	Result	Description
`\'`	`'`	Single quote
`\"`	`"`	Double quote
`\\`	`\`	Backslash

let x = "We are the so-called \"Vikings\" from the north.";

4. Template Literals (ES6)

Template Literals use backticks (``) rather than quotes to define a string. With template literals, you can use both single and double quotes inside a string:

let text = `He's often called "Johnny"`;

Template literals also allow multi-line strings:

let text = 
`The quick
brown fox
jumps over
the lazy dog`;

5. String Interpolation

Template literals allow variables and expressions in strings:

let firstName = "John";
let lastName = "Doe";
let text = `Welcome ${firstName}, ${lastName}!`;

String interpolation is the preferred way to join (concatenate) strings in modern JavaScript development.

Strings & Templates

Expert Answer & Key Takeaways

JavaScript Strings

1. Quotes and Strings

2. String Length

3. Escape Characters

4. Template Literals (ES6)

5. String Interpolation

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Found an issue or have a suggestion?

Strings & Templates

Expert Answer & Key Takeaways

JavaScript Strings

1. Quotes and Strings

2. String Length

3. Escape Characters

4. Template Literals (ES6)

5. String Interpolation

Top Interview Questions

?Interview Question

?Interview Question

?Interview Question

Course4All Engineering Team

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