Group, restructure and count array of object data based on another array in JavaScript

Curriculum Help
1

I have this array of object:

let attend = [
    {
        style: 'Big',
        date: '03/01/2016'
    },
    {
        style: 'Big',
        date: '03/01/2016'
    },
    {
        style: 'Small',
        date: '04/01/2016'
    },
    {
        style: 'Small',
        date: '03/01/2016'
    },
    {
        style: 'Big',
        date: '01/01/2016'
    }
]

and this array: let now = ['01/01/2016', '02/01/2016', '03/01/2016']

which I’d like to use in comparing, counting, and formating the array of object BASED on the date, in summary, I’d want the result to look like this:

 {
            name: 'Big',
            data: [1, 0, 2]
        },
     {
            name: 'Small',
            data: [0, 0, 2]
      }

Any suggestion would be appreciated, thanks a lot

2

This is how i did in the shortest possible time and it’s not the most efficient solution but does the job.

let attend = [
    {
        style: 'Big',
        date: '03/01/2016'
    },
    {
        style: 'Big',
        date: '03/01/2016'
    },
    {
        style: 'Small',
        date: '04/01/2016'
    },
    {
        style: 'Small',
        date: '03/01/2016'
    },
    {
        style: 'Big',
        date: '01/01/2016'
    }
];

let now = ['01/01/2016', '02/01/2016', '03/01/2016'];

let intitalValueArr = [];
let middlewareObj = {};

//inserting 0 in the array for intialization in the code
now.forEach(element => {
	intitalValueArr.push(0);
});

//manipulating and storing the data for easy formatting
for (let i = 0; i < now.length; i++) {
	attend.forEach(element => {
		if (element.date === now[i]) {
			//checking if the style already exist in the middleware object
			if (middlewareObj.hasOwnProperty(element.style)) {
				middlewareObj[element.style][i]++;
			} else {
				middlewareObj[element.style] = [...intitalValueArr];
				middlewareObj[element.style][i]++;
			}
		}
	});
}

//now formatting the unformatted middlewareObj
let formattedArr = [];
Object.keys(middlewareObj).forEach(element => {
	let insertObj = {};
	insertObj[element] = middlewareObj[element];
	formattedArr.push(insertObj);
});

console.log(formattedArr);
3

Oh kashimi, you are a lifesaver. Thank you very very MUCH, I really appreciate it!