unary (Lodash Compatibility)

Use ary from es-toolkit instead

This unary function is implemented as a special case of the ary function. If you need more control, it's more efficient to use ary from es-toolkit directly.

Use faster, more modern ary from es-toolkit instead.

Limits a function to accept at most one argument.

const limitedFunc = unary(func);

Reference

unary(func)

Use unary when you want to limit a function to accept at most one argument. Any additional arguments passed will be ignored.

import { unary } from 'es-toolkit/compat';

function greet(name, greeting, punctuation) {
  return `${greeting} ${name}${punctuation}`;
}

// Convert to a function that accepts only the first argument
const greetOne = unary(greet);
greetOne('Alice', 'Hello', '!'); // Works the same as greet('Alice')

// Useful when used with array's map function
const numbers = ['1', '2', '3'];
numbers.map(parseInt); // [1, NaN, NaN] - unexpected result
numbers.map(unary(parseInt)); // [1, 2, 3] - correct result

Parameters

• func ((...args: any[]) => any): The function to limit arguments for.

Returns

((...args: any[]) => any): Returns a new function that accepts at most one argument.