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JavaScript

// write a functin that takes an array as a parameter and returns a flattened array.
// example flatten([]) => []
// flatten([1, 2, 3]) => [1, 2, 3]
// flatten([1, 2, [3, 4]]) => [1, 2, 3, 4]

const getFlatArray = (array = []) => {
	 return array.map((o) => {
     if(o.length) {
     		return getFlatArray(o);
		 } else {
     		return o;
     }
		})
}
const flatten = (array) => {
		let results = getFlatArray(array)
    console.log(results)
}

console.log('hi')