breakNumberIntoObject.js

// Using Repeat
const breakNumberIntoObject = (inputNumber) => {
	if(!Number(inputNumber)) {
		return;
	}

	const inputNumberArray = String(inputNumber).split('');
	const output = {};

	inputNumberArray.map((num) => {
		const repeatedKey = num.repeat(Number(num));
		Object.assign(output, {[num]: repeatedKey});
	});

	console.log(output);
};

breakNumberIntoObject(125);
breakNumberIntoObject(5125);

// Using simple loop!!!
const breakNumberIntoObjectWithForLoop = (inputNumber) => {
	if(!Number(inputNumber)) {
		return;
	}

	const inputNumberArray = String(inputNumber).split('');
	let output = [];

	inputNumberArray.map((num) => {
		let a = '';
		for (let index = 1; index <= Number(num); index++) {
			a += num;
		}
		output.unshift({[num]: a});
	});

	output = Object.assign({}, ...output);

	console.log(output);
};

breakNumberIntoObjectWithForLoop(432);
breakNumberIntoObjectWithForLoop(5125);