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cloneWith

Performs a shallow clone of a value, invoking a customizer function to transform cloned values. If the customizer returns a defined value, it will be used instead of the default clone logic.

Usage Scenarios

  • Custom Transformation: When you need to modify values during cloning.
  • Selective Cloning: When certain properties need special handling during cloning.
  • Data Normalization: When cloned values need to be normalized or transformed.

Examples

import { cloneWith } from 'funtool';

// Increment numbers during clone
const obj = { a: 1, b: 2 };
const result = cloneWith(obj, (val) => typeof val === 'number' ? val + 1 : undefined);
// result => { a: 2, b: 3 }

// Transform dates to ISO strings
const withDate = { created: new Date() };
const dateClone = cloneWith(withDate, (val) => val instanceof Date ? val.toISOString() : undefined);
// dateClone => { created: "2023-07-20T12:34:56.789Z" }

// Filter out undefined values
const data = { a: 1, b: undefined, c: 3 };
const filtered = cloneWith(data, (val) => val !== undefined ? val : undefined);
// filtered => { a: 1, c: 3 }

Signature

type Customizer<T> = T extends any[]
  ? (val: T[number], index: number) => T[number] | undefined
  : T extends object
  ? (val: T[keyof T], key: keyof T) => T[keyof T] | undefined
  : never;
  
function cloneWith<T>(value: T, customizer: Customizer<T>): T

Parameters

  • value (T): The value to clone.
  • customizer (Customizer<T>): Function that transforms cloned values.

Returns

  • (T): The cloned value with custom transformations applied.
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