CONSTANT_CASE Converter Convert text to CONSTANT_CASE (SCREAMING_SNAKE_CASE) for constants.

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CONSTANT_CASE Converter

Convert text to CONSTANT_CASE (SCREAMING_SNAKE_CASE) for constants.

Paste Your Source Text

Type or paste text to convert to CONSTANT_CASE.

Review the CONSTANT_CASE Output

See text in uppercase with underscores between words.

Copy & Use

Copy for use as constant names or environment variables.

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What Is CONSTANT_CASE Converter?

A CONSTANT_CASE converter transforms text into CONSTANT_CASE (also called SCREAMING_SNAKE_CASE), where all letters are uppercase and words are separated by underscores. Developers use it to follow the constant naming convention when defining constants, environment variables, and configuration keys in their code. One specific problem it solves is the manual conversion of camelCase or snake_case text into CONSTANT_CASE, which can be error-prone and time-consuming.

It processes input text line by line, splitting each line into words based on spaces, underscores, hyphens, periods, and uppercase letters. This allows it to handle a variety of input formats, including those with punctuation and mixed case. The tool then converts each word to uppercase and joins them back together with underscores, resulting in the desired CONSTANT_CASE format.

What makes this tool different is its ability to automatically split words based on context, using regular expressions to identify boundaries between words. For example, it correctly splits "apiBaseUrl" into "API_BASE_URL", demonstrating its understanding of common naming conventions. By providing a simple online interface for converting text to CONSTANT_CASE, it simplifies the process of adhering to this convention when working with constants and configuration keys. Users can simply paste their text and get the converted output in SCREAMING_SNAKE_CASE format, such as "MAX_RETRIES" or "API_BASE_URL".

Why Use CONSTANT_CASE Converter?

Universal convention for constants in all major programming languages
Standard for environment variables and configuration keys
Visual distinction from regular variables
Handles conversion from any input format
Essential for .env files and config definitions

Common Use Cases

Constants Definition

Format constant names following language conventions: MAX_RETRY_COUNT, DEFAULT_TIMEOUT, API_VERSION.

Environment Variables

Create properly formatted .env variable names: DATABASE_URL, JWT_SECRET, NODE_ENV.

Configuration Keys

Standardize configuration constants for application settings files.

Enum Values

Generate CONSTANT_CASE enum values used in many languages for status codes and categories.

Technical Guide

The tool's word-splitting logic relies on regular expressions to identify boundaries between words, specifically using the `replace` method with patterns like `/([a-z])([A-Z])/g` and `/([A-Z]+)([A-Z][a-z])/g`. This allows it to correctly handle camelCase inputs by inserting spaces before uppercase letters. Additionally, it uses `/[_\-./]/g` to replace underscores, hyphens, periods, and other separators with spaces, effectively normalizing the input format. The `splitWords` function then splits the input string into an array of words using `\s+` as the delimiter, filters out empty strings, and trims any leading or trailing whitespace.

The conversion process itself is implemented using the `map` method, which applies the `toUpperCase` method to each word in the array. The resulting uppercase words are then joined back together with underscores using the `join` method. This approach ensures that the output is always in CONSTANT_CASE format, regardless of the input's original case or formatting. The tool's use of React's `useCallback` hook also helps optimize performance by memoizing the `onProcess` function and preventing unnecessary re-renders. When processing multi-line inputs, it splits the input string into an array of lines using `\n` as the delimiter, applies the conversion process to each line individually, and then joins the results back together with newline characters.

Tips & Best Practices

1
Use CONSTANT_CASE for values that never change: PI, MAX_INT, DEFAULT_TIMEOUT
2
Environment variables should always be CONSTANT_CASE: DATABASE_URL, API_KEY
3
In JavaScript, Object.freeze() with CONSTANT_CASE names clearly signals immutability
4
Python constants are CONSTANT_CASE by convention, though not enforced by the language
5
Group related constants with a common prefix: COLOR_RED, COLOR_BLUE, COLOR_GREEN

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Frequently Asked Questions

Q What is CONSTANT_CASE?

CONSTANT_CASE uses all uppercase letters with underscores between words: MAX_VALUE, API_BASE_URL, DEFAULT_TIMEOUT.

Q Why is it called SCREAMING_SNAKE_CASE?

It's snake_case (underscores between words) but "screaming" because all letters are uppercase, like shouting.

Q Which languages use CONSTANT_CASE?

Virtually all: JavaScript, Python, Java, C, C++, Ruby, Go, Rust, and more use CONSTANT_CASE for constants.

Q Are environment variables always CONSTANT_CASE?

By overwhelming convention, yes. Environment variables use CONSTANT_CASE across all operating systems and platforms.

Q Is CONSTANT_CASE enforced by compilers?

In most languages, it's a convention, not a requirement. Rust and some linters will warn if constants don't use this format.

About This Tool

CONSTANT_CASE Converter is a free online tool by FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration or installation required.