{"id":13349,"library":"is-type","title":"is-type","description":"The `is-type` package provides a collection of utility functions for JavaScript type checking, mirroring functionalities often found in Node.js's `util.types` module, but exposed through a direct `is` object for easier access. Released at version `0.0.1` in 2013, this package is effectively unmaintained and has seen no updates since its initial publication. Its primary differentiation was offering a 'nicer API' compared to alternatives like `core-util-is`. Due to its age and lack of maintenance, it is not recommended for new projects. Current stable alternatives are either native JavaScript type checks, TypeScript, or modern utility libraries that provide similar functionality and better compatibility with contemporary JavaScript module systems and environments. It operates exclusively using CommonJS modules.","status":"abandoned","version":"0.0.1","language":"javascript","source_language":"en","source_url":"git://github.com/juliangruber/is-type","tags":["javascript","type","checking","is","util","types"],"install":[{"cmd":"npm install is-type","lang":"bash","label":"npm"},{"cmd":"yarn add is-type","lang":"bash","label":"yarn"},{"cmd":"pnpm add is-type","lang":"bash","label":"pnpm"}],"dependencies":[],"imports":[{"note":"This package was published in 2013 and is exclusively CommonJS; it does not support ES Modules. Attempting to import it using ES module syntax will fail.","wrong":"import is from 'is-type';","symbol":"is","correct":"const is = require('is-type');"},{"note":"The package exposes a single `is` object with all type-checking methods. Destructuring directly from `require('is-type')` is not supported.","wrong":"const { array } = require('is-type');","symbol":"is.array","correct":"const is = require('is-type');\nis.array([]);"}],"quickstart":{"code":"const is = require('is-type');\n\n// Check basic types\nconsole.log('Is [1] an array?', is.array([1]));\nconsole.log('Is \"hello\" a string?', is.string('hello'));\nconsole.log('Is 123 a number?', is.number(123));\nconsole.log('Is true a boolean?', is.boolean(true));\nconsole.log('Is null null?', is.null(null));\nconsole.log('Is undefined undefined?', is.undefined(undefined));\n\n// Check for null or undefined\nconsole.log('Is null or undefined (null)?', is.nullOrUndefined(null));\nconsole.log('Is null or undefined (undefined)?', is.nullOrUndefined(undefined));\nconsole.log('Is null or undefined (0)?', is.nullOrUndefined(0));\n\n// Check objects and functions\nconsole.log('Is {} an object?', is.object({}));\nconsole.log('Is function(){} a function?', is.function(() => {}));\nconsole.log('Is new Date() a date?', is.date(new Date()));\nconsole.log('Is new RegExp() a RegExp?', is.regExp(/a/));\n\n// Check primitives\nconsole.log('Is true a primitive?', is.primitive(true));\nconsole.log('Is {} a primitive?', is.primitive({}));\n\n// A buffer check (Node.js specific)\ntry {\n  console.log('Is Buffer.from(\"hi\") a buffer?', is.buffer(Buffer.from('hi')));\n} catch (e) {\n  console.log('Buffer type check skipped (likely non-Node.js environment or Buffer not defined)');\n}","lang":"javascript","description":"Demonstrates common type checks using the `is` object, including checks for arrays, strings, numbers, booleans, null, undefined, objects, functions, dates, regular expressions, primitives, and buffers (Node.js specific)."},"warnings":[{"fix":"Use `const is = require('is-type');` for all imports. For modern projects requiring ESM, consider alternative type-checking libraries or native JavaScript checks.","message":"This package is an old CommonJS module (v0.0.1 from 2013) and does not support ES Modules. Using `import` statements will result in runtime errors.","severity":"breaking","affected_versions":">=0.0.1"},{"fix":"Avoid using this package for new projects. Migrate existing projects to actively maintained alternatives or native JavaScript type checks (e.g., `typeof`, `instanceof`, `Array.isArray()`, `Object.prototype.toString.call()`).","message":"The `is-type` package has been abandoned since its initial release in 2013. It is not maintained, may have unaddressed bugs or security vulnerabilities, and does not keep up with modern JavaScript features or environments.","severity":"gotcha","affected_versions":">=0.0.1"},{"fix":"When using in a browser environment, be aware that Node.js-specific checks will fail. Consider conditional checks or ensure your build process adequately shims Node.js globals if necessary.","message":"Some type checks, particularly `is.buffer()`, rely on Node.js-specific global objects (`Buffer`). This package is primarily intended for Node.js environments and may not function correctly or might throw errors in browser environments without proper polyfills or build configurations.","severity":"gotcha","affected_versions":">=0.0.1"}],"env_vars":null,"last_verified":"2026-04-19T00:00:00.000Z","next_check":"2026-07-18T00:00:00.000Z","problems":[{"fix":"Ensure your environment is set up for CommonJS (e.g., a Node.js script without `\"type\": \"module\"` in package.json) or switch to a different type-checking library that supports ES Modules.","cause":"Attempting to use `require()` in an ES Module context or a browser without a CommonJS loader.","error":"ReferenceError: require is not defined"},{"fix":"Verify that `npm install is-type` was successful. Ensure you are importing the package correctly using `const is = require('is-type');` and that the `is` variable is in scope when calling its methods.","cause":"The `is-type` package was not correctly imported or installed, or the `is` object is not accessible.","error":"TypeError: is.array is not a function"}],"ecosystem":"npm","meta_description":null,"install_score":null,"install_tag":null,"quickstart_score":null,"quickstart_tag":null,"pypi_latest":null,"cli_name":null,"cli_version":null}