{"id":12947,"library":"chainsaw","title":"Chainsaw (Fluent Interface Builder)","description":"chainsaw by Substack is a Node.js module designed to simplify the creation of chainable fluent interfaces in JavaScript. Released as version `0.1.0` in 2011, it provides a meta-module for authors to define methods that progress a workflow using `saw.next()` for sequential steps and `saw.nest()` for nested operations. This allows developers to build highly readable, method-chained APIs for complex asynchronous flows. The library operates in two modes: \"full mode,\" which records every action enabling features like `jump()`, `trap()`, and `down()` for replaying or manipulating the chain; and a more performant \"light mode\" (accessed via `Chainsaw.light()`) where actions are not recorded, conserving memory for long-lived chains. `chainsaw` includes `traverse` as a dependency for object manipulation. This package is specifically for Node.js fluent interface construction and should not be confused with the Kubernetes testing tool or the Windows forensic analysis tool that share the same name. Given its last release date over a decade ago, the package is effectively abandoned, with no ongoing development or official support, which could pose compatibility challenges with modern Node.js environments.","status":"abandoned","version":"0.1.0","language":"javascript","source_language":"en","source_url":"git://github.com/substack/node-chainsaw","tags":["javascript","chain","fluent","interface","monad","monadic"],"install":[{"cmd":"npm install chainsaw","lang":"bash","label":"npm"},{"cmd":"yarn add chainsaw","lang":"bash","label":"yarn"},{"cmd":"pnpm add chainsaw","lang":"bash","label":"pnpm"}],"dependencies":[{"reason":"Used internally for object traversal to manage the chain's state.","package":"traverse","optional":false}],"imports":[{"note":"This package is CommonJS-only and does not support ES module imports.","wrong":"import Chainsaw from 'chainsaw';","symbol":"Chainsaw","correct":"const Chainsaw = require('chainsaw');"},{"note":"The `light` factory is accessed as a static method on the main `Chainsaw` export, not a separate named export. It's used to create chains that do not record history for performance reasons.","wrong":"import { light } from 'chainsaw';","symbol":"Chainsaw.light","correct":"const LightChainsaw = Chainsaw.light(function (saw) { /* ... */ });"}],"quickstart":{"code":"const Chainsaw = require('chainsaw');\n\n// Define a constructor function for your chainable interface\nfunction CalculatorChain(initialValue) {\n  // Return a Chainsaw instance\n  return Chainsaw(function (saw) {\n    let currentValue = initialValue;\n\n    // Define chainable methods\n    this.add = function (n) {\n      currentValue += n;\n      console.log(`Added ${n}. Current value: ${currentValue}`);\n      saw.next(); // Move to the next step in the chain\n    };\n\n    this.subtract = function (n) {\n      currentValue -= n;\n      console.log(`Subtracted ${n}. Current value: ${currentValue}`);\n      saw.next();\n    };\n\n    this.multiply = function (n) {\n      currentValue *= n;\n      console.log(`Multiplied by ${n}. Current value: ${currentValue}`);\n      saw.next();\n    };\n\n    this.getResult = function (callback) {\n      console.log(`Executing getResult with final value: ${currentValue}`);\n      saw.nest(callback, currentValue); // Pass result to a nested callback\n    };\n  });\n}\n\n// Use the chainable interface\nconsole.log('Starting calculation chain...');\nCalculatorChain(10)\n  .add(5)\n  .subtract(2)\n  .multiply(3)\n  .getResult(function (finalSum) {\n    console.log(`Chain completed. Final sum: ${finalSum}`);\n    if (finalSum > 30) {\n      console.log('Result is greater than 30.');\n    } else {\n      console.log('Result is not greater than 30.');\n    }\n  });\n\n// Example with light mode\nconsole.log('\\nStarting light mode chain...');\nconst LightCalculator = Chainsaw.light(function (saw) {\n  let currentValue = 0;\n  this.add = function (n) {\n    currentValue += n;\n    console.log(`[Light Mode] Added ${n}. Current value: ${currentValue}`);\n    saw.next();\n  };\n  this.finish = function (callback) {\n    console.log(`[Light Mode] Finishing with value: ${currentValue}`);\n    saw.nest(callback, currentValue);\n  };\n});\n\nLightCalculator()\n  .add(10)\n  .add(20)\n  .finish(function (result) {\n    console.log(`[Light Mode] Final result: ${result}`);\n  });","lang":"javascript","description":"Demonstrates how to define and use a fluent interface with `chainsaw`, showcasing sequential steps (`saw.next()`) and nested callbacks (`saw.nest()`), including an example of the memory-optimized 'light mode'."},"warnings":[{"fix":"Determine if your application requires chain replay/manipulation. If so, use the default `Chainsaw()` constructor (full mode). If performance and memory are critical for very long chains and replay is not needed, use `Chainsaw.light()` and avoid the disabled methods.","message":"Chainsaw offers two modes: 'full' and 'light'. In 'light' mode (created with `Chainsaw.light()`), actions are not recorded, which disables features like `jump()`, `trap()`, and `down()` for replaying or manipulating the chain. Attempting to use these methods in 'light' mode will result in errors.","severity":"breaking","affected_versions":">=0.1.0"},{"fix":"For long-running processes or chains with many steps, consider using `Chainsaw.light()` to disable action recording. Profile your application's memory usage to identify if full mode is causing issues.","message":"The 'full mode' of Chainsaw records every action, which can lead to significant memory consumption for very long-lived or complex chains. This can impact application performance and stability.","severity":"gotcha","affected_versions":">=0.1.0"},{"fix":"For new projects, explore modern alternatives for fluent interface design or state management, such as libraries leveraging Promises, async/await, or reactive programming paradigms. For existing projects, evaluate the risks of using an unmaintained dependency.","message":"The `chainsaw` package (substack/node-chainsaw) has not seen updates since its `0.1.0` release in 2011 and is effectively abandoned. It may not be compatible with modern Node.js versions or maintainers may not address critical issues.","severity":"deprecated","affected_versions":">=0.1.0"},{"fix":"Always verify the package author and purpose. When scanning dependencies for vulnerabilities, be aware that tools might incorrectly flag `node-chainsaw` with CVEs belonging to other 'Chainsaw' projects (e.g., CVE-2020-9493 and CVE-2022-23307 are for Apache Chainsaw, not this package).","message":"The name 'chainsaw' is also used by other active and distinct projects, including a Kubernetes testing tool and a Windows forensic analysis tool. Ensure you are referencing the correct `node-chainsaw` package by Substack to avoid confusion and false-positive security alerts.","severity":"gotcha","affected_versions":">=0.1.0"}],"env_vars":null,"last_verified":"2026-04-19T00:00:00.000Z","next_check":"2026-07-18T00:00:00.000Z","problems":[{"fix":"Use the CommonJS `require()` syntax: `const Chainsaw = require('chainsaw');`","cause":"The `chainsaw` package is a CommonJS module and does not support ES module `import` syntax.","error":"ReferenceError: require is not defined in ES module scope"},{"fix":"Ensure all chainable methods are defined as `this.methodName = function (args) { ... saw.next(); }` within the `Chainsaw` constructor callback, and that `saw` is correctly passed and referenced.","cause":"This typically occurs if `saw.next()` or `saw.nest()` are called outside the context of a method defined within the `Chainsaw` constructor function, or if `Chainsaw` itself is not properly initialized.","error":"TypeError: Cannot read properties of undefined (reading 'next')"}],"ecosystem":"npm","meta_description":null,"install_score":null,"install_tag":null,"quickstart_score":null,"quickstart_tag":null,"pypi_latest":null,"cli_name":""}