util.styleText(format, text[, options]) function in Node.js

One useful function in Node.js for formatting and decorating text output on the console is util.styleText(format, text[, options]). The format option, which might include colors or text styles (such as bold or underline), defines the style or format used. The text argument is the string that will have the format selected applied to it. Additional parameters, such as color codes or style settings, might be included in optional options. By improving the readability of console output and simplifying the process of distinguishing between different kinds of information, this function is beneficial. It uses ANSI escape codes to apply styles, which are extensively supported by modern terminal emulators. Better text presentation in command-line applications is made possible through the util.styleText function, which is a part of the Node.js util module.

he expanded util.styleText() function in Node.js, which was released in versions 20.12.0 and 21.7.0. It is possibly supported by this function to customize text styles in the terminal, particularly about formatting and color. In these versions, the function also considers some environment variables that determine when to apply styles and colors.

Key Points:

Several key points of this function are as follows:

1. Formatting Codes: A format string may contain several styling codes, including text styles (bold, italic), color codes (green, red), and other text effects.
2. Terminal Support: In terminal environments that accept ANSI escape codes for styling, styling options are typically applied to text output. Certain styles and colors might not be acceptable in certain environments.
3. Utility: In command-line applications, the util.styleText function helps produce visually distinct text outputs that facilitate the highlighting of important information or status messages.

Syntax:

It has the following syntax:

Parameters:

• Format: This text contains instructions for the formatting and style that should be used on the text. It may contain a variety of style codes or placeholders to specify how the text should appear in the terminal. Common format options include bold, italic, color coding, etc.
• Text: It is the actual text that we want to format and style. It will be styled according to the format string provided.
• Options: This object can have more formatting customization options. Depending on the particular formatting requirements, these options may change.

Return Value:

1. Styled Text: The formatted text is a string that has been styled (e.g., bold, italic, underlined, colored, etc.) by the format parameter.
2. Options Modifications: The options parameter might allow additional configurations, such as setting specific colors, background colors, or other attributes.

Example:

Let us take an example to illustrate the util.styleText(format, text[, options]) function in Node.js.

Output:

 
Hello, World!
This is an error message.
SUCCESS!
INFO Note: Read carefully.   

Explanation:

The provided code defines a custom styleText function that uses ANSI escape codes to format text in the terminal. In order to format strings, it first imports the util module from Node.js. Three parameters are accepted by the styleText function: format, text, and an optional options object. Different formatting options, such as bold, italic, and color mapping are mapped to corresponding ANSI escape codes using a styles object. If the format supplied is invalid, the function verifies its validity and throws an error. Additional features such as putting text in uppercase, appending a suffix, or adding a prefix are possible through the options object. It applies the selected style using util.format() after the formatted string has been prepared.

The example usage demonstrates how to apply text styles in bold, red, green, and blue. It also shows how formatting works with optional configurations such as uppercase and the addition of prefixes and suffixes.