Util

Node.js util module — general-purpose utility functions. Includes string formatting, object inspection, promisification, and type checks.

Module: node:util Support: Experimental Since: 1.1.0 Docs: Node.js Docs See also: https://nodejs.org/api/util.html

21 members: 19 supported, 2 undocumented

Static Methods

🟢 format(args)

Formats a string using printf-style substitution patterns (%s, %d, %o, etc.).

🟢 formatWithOptions(inspectOptions, args)

Like format(), but accepts an explicit util.inspect options object for the first argument.

🟢 inspect(value, options)

Returns a string representation of an object for debugging.

🟢 promisify(original)

Wraps a callback-based function so it returns a Promise.

🟢 inherits(constructor, superConstructor)

Sets up prototype inheritance between a constructor and a superclass.

🟢 isDeepStrictEqual(val1, val2, skipPrototype)

Returns true if two values are deeply equal using the strict equality algorithm.

🟢 deprecate(fn, msg, code, options)

Wraps a function to emit a deprecation warning when called.

🟢 debuglog(section)

Returns a logging function that writes to stderr only if the NODE_DEBUG env variable includes section.

🟢 callbackify(original)

Wraps an async function (or a function that returns a Promise) so it follows

🟢 getSystemErrorName(err)

Returns the string name for a numeric error code (the errno value).

🟢 getSystemErrorMessage(err)

Returns the string message for a numeric error code (the errno value).

🟢 getSystemErrorMap()

Returns a Map of all system error codes to [name, message] pairs.

🟢 toUSVString(string)

Returns a string after replacing any lone surrogates with the Unicode replacement character U+FFFD.

🟢 stripVTControlCharacters(str)

Removes ANSI escape codes (including color and cursor movement) from a string.

🟢 styleText(format, text, options)

Formats text with ANSI styling for terminal output.

🟢 getCallSites(frameCount, options)

Returns an array of call site objects representing the current call stack.

🟢 parseEnv(content)

Parses a .env file content string into a key-value object.

🟢 log(args)

Writes a formatted timestamp + message to stdout (similar to console.log but with a timestamp).

🟢 types

Writes a formatted timestamp + message to stdout (similar to console.log but with a timestamp).

⚪ TextEncoder

Object with type-checking predicates (e.g. util.types.isDate, util.types.isMap). @compat elide Full

⚪ TextDecoder

The WHATWG TextEncoder class. @compat elide Full

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static inherits(constructor: object, superConstructor: object)

static inherits(constructor: object, superConstructor: object)

Sets up prototype inheritance between a constructor and a superclass.

Parameter	Type	Description
`constructor`	object	The child constructor
`superConstructor`	object	The parent constructor

> Known issue: Deprecated; use ES6 class extends syntax instead