cond (Lodash Compatibility)

Use if-else or switch statements instead

This cond function performs slowly due to complex iteratee processing, array transformations, and function validation.

Use faster and clearer if-else or switch statements instead.

Creates a function that iterates through condition-function pairs, checking conditions in order and executing the first matching function.

const conditionFunction = cond(pairs);

Reference

cond(pairs)

Use cond when you want to check multiple conditions in order and execute the function corresponding to the first true condition. This is useful for expressing complex conditional logic in a functional style.

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

// Basic usage
const getValue = cond([
  [x => x > 10, x => 'big'],
  [x => x > 5, x => 'medium'],
  [x => x > 0, x => 'small'],
  [() => true, () => 'zero or negative'],
]);

console.log(getValue(15)); // "big"
console.log(getValue(8)); // "medium"
console.log(getValue(3)); // "small"
console.log(getValue(-1)); // "zero or negative"

You can also use it for object pattern matching.

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

const processUser = cond([
  [user => user.role === 'admin', user => `Admin: ${user.name}`],
  [user => user.role === 'user', user => `User: ${user.name}`],
  [user => user.role === 'guest', user => `Guest: ${user.name}`],
  [() => true, () => 'Unknown role'],
]);

console.log(processUser({ name: 'John', role: 'admin' })); // "Admin: John"
console.log(processUser({ name: 'Jane', role: 'user' })); // "User: Jane"

Only the first true condition is executed. If all conditions are false, it returns undefined.

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

const checkValue = cond([
  [x => x > 10, x => 'greater than 10'],
  [x => x < 5, x => 'less than 5'],
]);

console.log(checkValue(15)); // "greater than 10"
console.log(checkValue(3)); // "less than 5"
console.log(checkValue(7)); // undefined (no matching condition)

Parameters

• pairs (Array<[predicate, func]>): An array of pairs consisting of condition functions and functions to execute.

Returns

((...args: any[]) => unknown): Returns a new function that checks conditions and executes the first matching function.