@arcjet/sprintf

@arcjet/sprintf

Arcjet platform-independent replacement for util.format.

This package is platform-independent in order to support multiple runtimes in varying environments, such as Edge Runtime, Node.js, Bun, Deno, and Cloudflare Workers.

• npm package (@arcjet/sprintf)
• GitHub source code (sprintf/ in arcjet/arcjet-js)

Installation

npm install -S @arcjet/sprintf

Example

import format from "@arcjet/sprintf";

format("Hello %s", "world") === "Hello world";
format("1 %i %d", 2, 3.0) === "1 2 3";

Substitutions

Substitutions will be made for the following character sequences if the matching argument conforms to the type. For example, "%d" will only be replaced by a number, not a string or object.

Object substitution supports any value that is not undefined.

• %d | %f - Replaced if provided with a number.
• %i - Replaced if provided with a number after Math.floor is called on it.
• %O | %o | %j - Replaced if provided with any value after JSON.stringify is called on it. Objects with circular references will be replaced with [Circular]. Functions will be replaced with the function name or <anonymous> if unnamed.
• %s - Replaced if provided with a string.
• %% - Replaced by the literal % character.

Implementation

This implementation of this library is based on quick-format-unescaped, which is licensed MIT with licenses included in our source code.

The goal of this library is to be more restrictive than quick-format-unescaped while maintaining as much compatibility as possible, since pino uses it to format strings.

License

Licensed under the Apache License, Version 2.0.

Changelog

1.0.0-beta.9 (2025-07-09)

🚀 New Features

• add Fastify integration (#4538) (d5922e4)
• protocol: Add Fastify stack (#4570) (538818d)

🪲 Bug Fixes

• bun: Rely on connect-web to communicate from Bun runtime (#4523) (c9b26b0)

📝 Documentation

• add compatibility section (#4517) (506da27)
• Add relevant links to each package readme (#4429) (2653ab0)

🧹 Miscellaneous Chores

• Add keywords to package.jsons (#4408) (4f09478)
• arcjet: Reduce timeouts and other transport issues to info log (#4411) (c148bab)
• astro: add temporary warning message for fully static sites (#4278) (6d093be)
• astro: Increase minimum peerDependency (#4432) (a0453e2), closes #3094
• Ensure all sample code checking .isDenied() returns error response. (#4552) (8fc2d2d)
• example: fix typo in svelte example (#4518) (6b72298)
• Fix jco name in dependabot (#4371) (809fe76)
• Fix missing file extension in test (#4407) (b694dad)
• Fix Rollup on Node 24 (#4406) (1853b1a)
• improve Astro SDK description (#4491) (00482c5)
• remove expect, references to jest (#4415) (2c44c39)

⌨️ Code Refactoring

• Clean files fields in package.jsons (#4441) (fd7913b)
• remove unneeded nbsp with regular space (#4503) (274114d)
• rename use of deprecated method name (#4504) (2b30a4d)

📚 Tests

• add actual tests for reasons (#4516) (768f85e)
• add tests for analyze (#4564) (7ef59bb)
• clean cache tests (#4472) (92b7335)
• clean protocol tests (#4479) (c67d517)
• rename confusing test cases (#4515) (fe20b6d)

🔨 Build System

• add separate core, coverage tests (#4480) (61c2c50)

✅ Continuous Integration

• Add Node.js 22, 24 (#4414) (0fa6743)