JavaScript String Methods

This page provides the most commonly used JavaScript string methods that help you manipulate strings effectively.

Section 1. Searching #

Mastering the string search methods can help you analyze text more efficiently. These sections introduce the string search methods that allow you to locate and verify substrings within strings.

search() – locate a substring in a string using a regular expression.
indexOf() – get the index of the first occurrence of a substring in a string.
lastIndexOf() – find the index of the last occurrence of a substring in a string.
includes() – check if a string contains a substring.
startsWith() – check if a string starts with another string.
endsWith() – determine if a string ends with another string.

Section 2. Trimming #

This section introduces the string trimming methods that allow you to remove unwanted whitespace characters from a string, ensuring your text is clean and well-formatted.

trim() – remove whitespace characters from a string.
trimStart() – remove the leading whitespace characters of a string.
trimEnd() – remove the ending whitespace characters of a string.

Section 3. Padding #

Padding strings is a useful technique for formatting text. This section introduces two string methods padStart() and padEnd() for padding strings.

padStart() – pad the beginning of a string with another string until the resulting string reaches a specified length.
padEnd() – pad the end of a string with another string until the resulting string reaches a certain length.

Section 4. Extracting #

This section introduces the extracting string methods that allow you to break down strings into smaller pieces and extract specific substrings:

split() – split a string into an array of substrings.
substring() – extract a substring from a string.
slice() – extract a part of a string.

Section 5. Concatenating & interpolating #

Learn how to concatenate strings and substitute variables directly within strings using template literals.

concat() – concatenate multiple strings into a new string.
Template literals – learn how to use template literal to substitute variables directly within a string in a more flexible and readable way.

Section 6. Replacing #

This section introduces replacing string methods that allow you to perform data cleaning and transformation effectively.

replace() – replace a substring in a string with a new one.
replaceAll() – replace all occurrences of a substring that matches a pattern with a new one.

Section 7. Changing cases #

This section introduces various case-changing methods that allow you to convert characters in strings to lowercase or uppercase.

toUpperCase – return a string with all characters converted to uppercase.
toLowerCase – return a string with all characters converted to lowercase.

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