floorTo

const result = floorTo(4.129, 2);

console.log(result);
// 4.12

const result = floorTo(4.12, 2);

console.log(result);
// 4.12

console.log(floorTo(4.1, 0));
// 4

console.log(floorTo(4.9, 0));
// 4

console.log(floorTo(-4.123, 2));
// -4.13

console.log(floorTo(-4.1, 0));
// -5

console.log(floorTo(3.14159, 3));
// 3.141

console.log(floorTo(3.14159, 4));
// 3.1415

console.log(floorTo(1234, -2));
// 1200

console.log(floorTo(1250, -2));
// 1200

console.log(floorTo(Infinity, 2));
// Infinity

console.log(floorTo(-Infinity, 2));
// -Infinity

floorTo(NaN, 2);
// RangeError: floorTo: value must not be NaN

floorTo(4.123, 2.5);
// RangeError: floorTo: decimals must be an integer