Introduction to kind-of

kind-of is a versatile JavaScript library that allows developers to determine the type of a JavaScript value with ease. It offers a robust and efficient way to handle type-checking for various data types, including primitives, arrays, objects, and more.

Getting Started with kind-of

  
    // Install the kind-of library
    npm install kind-of

    // Require kind-of in your project
    const kindOf = require('kind-of');
  

Basic API Examples

  
    // Check for primitive types
    console.log(kindOf('hello')); // 'string'
    console.log(kindOf(42)); // 'number'
    console.log(kindOf(true)); // 'boolean'
    console.log(kindOf(null)); // 'null'
    console.log(kindOf(undefined)); // 'undefined'
    console.log(kindOf(Symbol('foo'))); // 'symbol'

    // Check for complex types
    console.log(kindOf([])); // 'array'
    console.log(kindOf({})); // 'object'
    console.log(kindOf(new Date())); // 'date'
    console.log(kindOf(new RegExp('foo'))); // 'regexp'
    console.log(kindOf(function() {})); // 'function'

    // Additional type checks
    console.log(kindOf(new Error())); // 'error'
    console.log(kindOf(Promise.resolve())); // 'promise'
    console.log(kindOf(Buffer.from('foo'))); // 'buffer'
  

Advanced API Examples

  
    // Check for specific object types
    console.log(kindOf(new Map())); // 'map'
    console.log(kindOf(new Set())); // 'set'
    console.log(kindOf(new WeakMap())); // 'weakmap'
    console.log(kindOf(new WeakSet())); // 'weakset'

    // Custom class instance
    class MyClass {}
    console.log(kindOf(new MyClass())); // 'object'
  

Application Example with kind-of

Here is a practical example of how kind-of can be used in a Node.js application to dynamically handle different input types.

  
    const kindOf = require('kind-of');

    function processInput(input) {
      switch (kindOf(input)) {
        case 'string':
          console.log('Processing string:', input);
          break;
        case 'number':
          console.log('Processing number:', input);
          break;
        case 'boolean':
          console.log('Processing boolean:', input);
          break;
        case 'array':
          console.log('Processing array:', input);
          input.forEach(item => processInput(item));
          break;
        case 'object':
          console.log('Processing object:', input);
          for (let key in input) {
            processInput(input[key]);
          }
          break;
        default:
          console.log('Unrecognized type:', kindOf(input));
      }
    }

    // Example usage:
    processInput('Hello World');
    processInput(123);
    processInput(true);
    processInput([1, 'foo', false]);
    processInput({ a: 1, b: 'bar', c: [2, 3] });
  

With kind-of, managing different data types becomes straightforward, enhancing the robustness and flexibility of your applications.

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