Template literals in Javascript - Step-by-Step Execution

Concept Flow - Template literals

Start

↓

Define variables

↓

Use backticks ` ` to create template literal

↓

Insert variables with ${}

↓

Evaluate expressions inside ${}

↓

Combine text and values

↓

Output final string

↓

End

Template literals use backticks and ${} to insert variables or expressions inside strings, producing a combined output.

Execution Sample

Javascript

const name = "Alice";
const age = 30;
const message = `Name: ${name}, Age: ${age}`;
console.log(message);

This code creates a message string using template literals to insert variables name and age.

Execution Table

Step	Action	Evaluation	Result
1	Define variable name	name = "Alice"	name = "Alice"
2	Define variable age	age = 30	age = 30
3	Create template literal	`Name: ${name}, Age: ${age}`	"Name: Alice, Age: 30"
4	Output message	console.log(message)	Prints: Name: Alice, Age: 30

💡 All variables inserted and output printed, execution ends.

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
name	undefined	"Alice"	"Alice"	"Alice"	"Alice"
age	undefined	undefined	30	30	30
message	undefined	undefined	undefined	"Name: Alice, Age: 30"	"Name: Alice, Age: 30"

Key Moments - 2 Insights

Why do we use backticks (`) instead of quotes for template literals?

Backticks allow embedding variables and expressions inside ${}, which normal quotes do not support, as shown in step 3 of the execution_table.

What happens inside the ${} in a template literal?

The expression inside ${} is evaluated and converted to a string, then inserted into the final string, as seen in step 3 where ${name} becomes "Alice".

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of message after step 3?

A "Name: ${name}, Age: ${age}"

B "Name: Alice, Age: 30"

C "Name: name, Age: age"

D undefined

💡 Hint

Check the 'Result' column in row for step 3 in execution_table.

At which step is the variable age assigned a value?

A Step 3

B Step 1

C Step 2

D Step 4

💡 Hint

Look at the 'Action' and 'Evaluation' columns in execution_table for when age is defined.

If we change name to "Bob", how would the message change at step 3?

A "Name: Bob, Age: 30"

B "Name: Alice, Age: 30"

C "Name: ${name}, Age: ${age}"

D "Name: , Age: 30"

💡 Hint

Refer to variable_tracker to see how changing name affects message in step 3.

Concept Snapshot

Template literals use backticks (`) to create strings.
Insert variables or expressions inside ${}.
Expressions inside ${} are evaluated and included.
Allows easy multi-line and readable strings.
Example: `Hello, ${name}!` outputs 'Hello, Alice!'.

Full Transcript

This example shows how template literals work in JavaScript. We start by defining variables name and age. Then we create a string using backticks and insert these variables inside ${}. The expressions inside ${} are evaluated and combined with the text to form the final string. Finally, we print the message. This method is easier and cleaner than using string concatenation.

Practice

1. What is the main purpose of using template literals in JavaScript?

easy

A. To comment code

B. To create arrays

C. To define functions

D. To easily insert variables and expressions inside strings

Solution

1. Step 1: Understand what template literals do

   Template literals allow embedding variables and expressions inside strings using ${}.

2. Step 2: Compare with other options

   Creating arrays, defining functions, and commenting code are unrelated to template literals.

3. Final Answer:

   To easily insert variables and expressions inside strings -> Option D

4. Quick Check:

   Template literals = insert variables in strings [OK]

Hint: Remember backticks and ${} insert variables easily [OK]

Common Mistakes:

• Confusing template literals with arrays
• Thinking template literals define functions
• Using template literals for comments

2. Which of the following is the correct syntax for a template literal in JavaScript?

easy

A. "Hello, ${name}!"

B. 'Hello, ${name}!'

C. `Hello, ${name}!`

D.

Solution

1. Step 1: Identify the correct delimiter for template literals

   Template literals use backticks (`), not single or double quotes.

2. Step 2: Check the options

   Only `Hello, ${name}!` uses backticks correctly around the string with ${name}.

3. Final Answer:

   `Hello, ${name}!` -> Option C

4. Quick Check:

   Backticks + ${} = template literal [OK]

Hint: Template literals always use backticks (`) [OK]

Common Mistakes:

• Using single or double quotes instead of backticks
• Forgetting to use ${} for variables
• Using angle brackets instead of quotes

3. What will be the output of the following code?

const name = "Alice";
const age = 25;
console.log(`Name: ${name}, Age: ${age + 5}`);

medium

A. Name: Alice, Age: 30

B. Name: Alice, Age: 25 + 5

C. Name: ${name}, Age: ${age + 5}

D. Name: Alice, Age: 25

Solution

1. Step 1: Evaluate the expressions inside ${}

   The variable name is "Alice" and age + 5 equals 30.

2. Step 2: Combine the string with evaluated values

   The template literal becomes "Name: Alice, Age: 30" when printed.

3. Final Answer:

   Name: Alice, Age: 30 -> Option A

4. Quick Check:

   Template literal evaluates expressions inside ${} [OK]

Hint: Expressions inside ${} are calculated before output [OK]

Common Mistakes:

• Treating ${} as plain text
• Not evaluating expressions inside ${}
• Confusing string concatenation with template literals

4. Find the error in the following code snippet:

const user = "Bob";
console.log('Hello, ${user}!');

medium

A. Using single quotes instead of backticks for template literal

B. Missing semicolon after console.log

C. Variable user is not declared

D. Incorrect use of console.log function

Solution

1. Step 1: Check string delimiters for template literals

   Template literals require backticks (`), but single quotes are used here.

2. Step 2: Understand effect of wrong quotes

   Using single quotes treats ${user} as plain text, not variable substitution.

3. Final Answer:

   Using single quotes instead of backticks for template literal -> Option A

4. Quick Check:

   Backticks needed for ${} substitution [OK]

Hint: Use backticks, not quotes, for variable substitution [OK]

Common Mistakes:

• Using single or double quotes instead of backticks
• Expecting ${} to work inside normal quotes
• Ignoring string delimiter rules

5. You want to create a multi-line string that includes a user's name and age using template literals. Which code correctly achieves this?

const name = "Eva";
const age = 28;
// Choose the correct code to print:
// Hello Eva,
// You are 28 years old.

hard

A. console.log(`Hello ${name},\nYou are ${age} years old.`);

B. console.log(`Hello ${name},
You are ${age} years old.`);

C. console.log('Hello ${name},\nYou are ${age} years old.');

D. console.log("Hello ${name},\nYou are ${age} years old.");

Solution

1. Step 1: Identify correct use of template literals and multi-line strings

   Template literals allow multi-line strings directly without \n escape sequences.

2. Step 2: Check each option

   console.log(`Hello ${name}, You are ${age} years old.`); uses backticks and writes the string on two lines, correctly showing multi-line output with variable substitution.

3. Final Answer:

   console.log(`Hello ${name}, You are ${age} years old.`); -> Option B

4. Quick Check:

   Backticks allow multi-line strings and ${} substitution [OK]

Hint: Use backticks and press Enter for multi-line strings [OK]

Common Mistakes:

• Using quotes instead of backticks for multi-line
• Using \n inside template literals unnecessarily
• Not substituting variables inside quotes