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# lodash.isnumber
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The lodash method `_.isNumber` exported as a standalone module. Checks if a value is classified as a Number primitive or object, returning true for numeric values including Number objects, and false for all other types.
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## Package Information
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- **Package Name**: lodash.isnumber  
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- **Package Type**: npm
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- **Language**: JavaScript
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- **Installation**: `npm install lodash.isnumber`
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## Core Imports
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```javascript
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const isNumber = require('lodash.isnumber');
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```
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ES6/ESM:
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```javascript
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import isNumber from 'lodash.isnumber';
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```
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## Basic Usage
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```javascript
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const isNumber = require('lodash.isnumber');
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// Primitive numbers
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isNumber(42);        // => true
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isNumber(3.14);      // => true
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isNumber(NaN);       // => true
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isNumber(Infinity);  // => true
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// Number objects
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isNumber(new Number(42)); // => true
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// Non-numbers
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isNumber('42');      // => false
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isNumber([1, 2, 3]); // => false
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isNumber({a: 1});    // => false
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isNumber(null);      // => false
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```
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## Capabilities
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### Number Type Checking
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Checks if a value is classified as a Number primitive or object. Follows ECMAScript 5 specification where NaN is considered a number type.
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```javascript { .api }
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/**
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 * Checks if value is classified as a Number primitive or object.
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 * Note: NaN is considered a number per ECMAScript 5 specification.
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 * 
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 * @param {*} value - The value to check
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 * @returns {boolean} - Returns true if value is a number, else false
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 */
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function isNumber(value);
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```
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**Behavior:**
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- Returns `true` for primitive numbers: `0`, `42`, `3.14`, `Infinity`, `-Infinity`, `NaN`
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- Returns `true` for Number objects: `new Number(0)`, `new Number(42)`
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- Returns `false` for all other types including:
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  - Strings (even numeric strings like `"42"`)
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  - Arrays, objects, functions
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  - Boolean values (`true`, `false`)
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  - `null` and `undefined`
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  - Dates, regular expressions
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**Examples:**
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```javascript
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const isNumber = require('lodash.isnumber');
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// Primitive numbers - all return true
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isNumber(0);           // => true
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isNumber(42);          // => true  
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isNumber(-17);         // => true
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isNumber(3.14159);     // => true
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isNumber(NaN);         // => true (per ECMAScript spec)
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isNumber(Infinity);    // => true
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isNumber(-Infinity);   // => true
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// Number objects - return true
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isNumber(new Number(0));    // => true
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isNumber(new Number(42));   // => true
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isNumber(new Number(NaN));  // => true
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// Non-numbers - all return false
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isNumber();                 // => false (undefined)
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isNumber(null);            // => false
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isNumber(false);           // => false
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isNumber(true);            // => false
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isNumber('42');            // => false (numeric string)
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isNumber('hello');         // => false
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isNumber([1, 2, 3]);       // => false
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isNumber({a: 1});          // => false
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isNumber(new Date());      // => false
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isNumber(/regex/);         // => false
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isNumber(function() {});   // => false
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// Edge cases
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isNumber(+"42");           // => true (string coerced to number)
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isNumber(parseInt("42"));  // => true (parsed to number)
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isNumber(parseFloat("3.14")); // => true (parsed to number)
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```
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**Implementation Details:**
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- Uses `typeof value == 'number'` to check for primitive numbers
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- Uses `Object.prototype.toString.call(value) == '[object Number]'` to detect Number objects
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- Handles cross-realm/frame Number objects correctly
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- No dependencies on other lodash functions