Curebase - technical interview- solution - Jesus Santander.

main.js

/**
 * This function determines if a given array input is a valid 'Montain number'
 * @param {number[]} arr the input array 
 * @returns {boolean} True if is valid 
 */
const isValidMountainArray = (arr) => {
    let isIncreasing = true;
    let isDecreasing = false;

    if(arr.length < 3) return false;
    if(arr[0] > arr[1]) return false;

    for(let i = 0; i < arr.length - 1; i++){
        if(typeof arr[i] !== "number") return false;
        if(arr[i] < 0) return false;
        if(arr[i] == arr[i+1]) return false;
        if(arr[i] > Math.pow(10,4)) return false;

        if(isIncreasing && arr[i] > arr[i+1]){
            isIncreasing = false;
            isDecreasing= true;
            continue;
        }

        if(isDecreasing && arr[i] < arr[i+1]){
            return false;
        }
    }

    if(!isDecreasing) return false;
    return true;
}


const isValidMountInArray_InputIsString_ShouldReturnFalse = () => {
    const caseScenario = ["a", 5, "b"];
    if(!isValidMountainArray(caseScenario)) throw Error(`It should return false on test case -> ${caseScenario}`)
}

const isValidMountainArray_InputGratherThan10pow4_ShouldReturnFalse = () => {
    const caseScenario = [0, 1, 100000, 1, 0];
    if (!isValidMountainArray(caseScenario)) throw Error(`It should return false on test case -> ${caseScenario}`)
}