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tessl/npm-lodash-castarray

Casts value as an array if it's not one

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Overview
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index.mddocs/

Lodash CastArray

Lodash CastArray provides a single utility function that converts any value to an array if it's not already one. It ensures consistent array-type outputs regardless of input type, making it ideal for normalizing function parameters that can accept either single values or arrays.

Package Information

  • Package Name: lodash.castarray
  • Package Type: npm
  • Language: JavaScript
  • Installation: npm install lodash.castarray

Core Imports

var castArray = require('lodash.castarray');

For ES modules (if using a bundler):

import castArray from 'lodash.castarray';

Basic Usage

var castArray = require('lodash.castarray');

// Convert single values to arrays
castArray(1);           // => [1]
castArray('hello');     // => ['hello']
castArray({ a: 1 });    // => [{ a: 1 }]
castArray(null);        // => [null]
castArray(undefined);   // => [undefined]

// Arrays are returned unchanged (reference preserved)
var arr = [1, 2, 3];
console.log(castArray(arr) === arr); // => true

// No arguments returns empty array
castArray();            // => []

Capabilities

Array Conversion

Converts any value to an array if it's not already one, with special handling for various input scenarios.

/**
 * Casts value as an array if it's not one
 * @param {*} [value] - The value to inspect
 * @returns {Array} Returns the cast array
 */
function castArray() {
  if (!arguments.length) {
    return [];
  }
  var value = arguments[0];
  return Array.isArray(value) ? value : [value];
}

Behavior Details:

  • No arguments: Returns empty array []
  • Array input: Returns the original array unchanged (maintains reference equality)
  • Non-array input: Wraps the value in a new array [value]
  • All types supported: Handles strings, numbers, objects, null, undefined, functions, etc.
  • No exceptions: Never throws errors, handles all input gracefully

Usage Examples:

var castArray = require('lodash.castarray');

// Single value normalization
function processItems(items) {
  // Ensure items is always an array
  items = castArray(items);
  return items.map(function(item) {
    return item.toUpperCase();
  });
}

processItems('hello');        // => ['HELLO']
processItems(['a', 'b']);     // => ['A', 'B']

// API parameter normalization
function deleteUsers(userIds) {
  userIds = castArray(userIds);
  userIds.forEach(function(id) {
    console.log('Deleting user:', id);
  });
}

deleteUsers(123);             // Works with single ID
deleteUsers([123, 456]);      // Works with array of IDs

// Conditional array operations
function safePush(arr, items) {
  items = castArray(items);
  return arr.concat(items);
}

var myArray = [1, 2];
safePush(myArray, 3);         // => [1, 2, 3]
safePush(myArray, [4, 5]);    // => [1, 2, 4, 5]

Performance Characteristics

  • Minimal overhead: Single condition check plus array creation when needed
  • Reference preservation: Array inputs return the same reference (no copying)
  • Native type checking: Uses Array.isArray for optimal performance
  • No iterations: Constant time operation regardless of input size

Error Handling

The castArray function is designed to never throw exceptions:

  • Accepts any number of arguments (uses only the first)
  • Handles all JavaScript types including null and undefined
  • No validation or type checking that could cause errors
  • Defensive programming approach with predictable fallback behavior

docs

index.md

tile.json