How to Iterate Over String in JavaScript: Simple Methods Explained

You can iterate over a string in JavaScript using a for loop, for...of loop, or string methods like split(). Each character in the string can be accessed one by one inside the loop using the string index or directly with for...of.

Syntax

Here are common ways to iterate over a string:

• For loop: Use an index to access each character by position.
• For...of loop: Directly access each character in the string.

javascript

const str = "hello";

// For loop syntax
for (let i = 0; i < str.length; i++) {
  const char = str[i];
  // use char
}

// For...of loop syntax
for (const char of str) {
  // use char
}

Example

This example shows how to print each character of a string on a new line using both for and for...of loops.

javascript

const text = "JavaScript";

console.log('Using for loop:');
for (let i = 0; i < text.length; i++) {
  console.log(text[i]);
}

console.log('Using for...of loop:');
for (const char of text) {
  console.log(char);
}

Output

Using for loop:
J
a
v
a
S
c
r
i
p
t
Using for...of loop:
J
a
v
a
S
c
r
i
p
t

Common Pitfalls

Some common mistakes when iterating over strings include:

• Using for...in loop, which iterates over property names, not characters.
• Modifying the string inside the loop (strings are immutable).
• Assuming string length changes during iteration.

javascript

const str = "hello";

// Wrong: for...in loops over indexes as strings, not characters
for (const index in str) {
  console.log(str[index]); // works but not recommended
}

// Right: for...of loops over characters directly
for (const char of str) {
  console.log(char);
}

Output

h
e
l
l
o
h
e
l
l
o

Quick Reference

Summary tips for iterating over strings in JavaScript:

• Use for loop with index for classic iteration.
• Use for...of loop for cleaner, direct character access.
• Avoid for...in for strings.
• Remember strings are immutable; do not try to change characters directly.

Key Takeaways

Use a for loop or for...of loop to iterate over each character in a string.

for...of loop is simpler and recommended for direct character access.

Avoid using for...in loop for strings as it iterates over indexes as strings.

Strings are immutable; do not try to modify characters inside loops.

Access characters by index with str[i] or directly with for...of.