Logical complement

OSCC · JavaScript, Function, Logic · Sep 15, 2020

Returns a function that is the logical complement of the given function, fn.

• Use the logical not (!) operator on the result of calling fn with any supplied args.

const complement = fn => (...args) => !fn(...args);

const isEven = num => num % 2 === 0;
const isOdd = complement(isEven);
isOdd(2); // false
isOdd(3); // true

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