iteratee

util

Creates a function that invokes the predicate at the path of a given object.

Installation

Import

import { iteratee } from '@tulx/utils';

Source Code

Implementation

/**
 * Creates a function that invokes the predicate at the path of a given object.
 *
 * @param func - The value to convert to a callback.
 * @returns Returns the callback.
 *
 * @example
 * ```ts
 * const users = [
 *   { 'user': 'barney' },
 *   { 'user': 'fred' }
 * ];
 * map(users, iteratee('user')); // ['barney', 'fred']
 * ```
 */
export function iteratee<T>(
  func: ((value: T) => unknown) | string | Record<string, unknown>
): (value: T) => unknown {
  if (typeof func === 'function') {
    return func;
  }
  if (typeof func === 'string') {
    return (value: T) => (value as Record<string, unknown>)[func];
  }
  if (typeof func === 'object' && func !== null) {
    return (value: T) => {
      for (const key in func) {
        if (Object.prototype.hasOwnProperty.call(func, key)) {
          if ((value as Record<string, unknown>)[key] !== func[key]) {
            return false;
          }
        }
      }
      return true;
    };
  }
  return identity;
}

function identity<T>(value: T): T {
  return value;
}

Example

import { iteratee } from '@tulx/utils';

const users = [
{ 'user': 'barney' },
{ 'user': 'fred' }
];
map(users, iteratee('user')); // ['barney', 'fred']

Related Functions

attempt

Attempts to invoke func, returning either the result or the caught error object.

bindAll

Binds methods of an object to the object itself, overwriting the existing method.

cond

Creates a function that iterates over pairs and invokes the corresponding function of the first predicate to return truthy.

conforms

Creates a function that invokes the predicate properties of source with the corresponding property values of a given object.

constant

Creates a function that returns value.

defaultTo

Checks value to determine whether a default value should be returned in its place.