Compare 2 arrays and combine in Javascript-CodePudding

How can i compare and combine 2 arrays using array functions of javascript or using lodash?

I have this initial array of dates for last 30 days.

[
  '2022-12-11', '2022-12-12', '2022-12-13',
  '2022-12-14', '2022-12-15', '2022-12-16',
  '2022-12-17', '2022-12-18', '2022-12-19',
  '2022-12-20', '2022-12-21', '2022-12-22',
  '2022-12-23', '2022-12-24', '2022-12-25',
  '2022-12-26', '2022-12-27', '2022-12-28',
  '2022-12-29', '2022-12-30', '2022-12-31',
  '2023-01-01', '2023-01-02', '2023-01-03',
  '2023-01-04', '2023-01-05', '2023-01-06',
  '2023-01-07', '2023-01-08', '2023-01-09',
  '2023-01-10', '2023-01-11'
]

Then this is the second with count value.

[ [ '2023-01-09', 1 ], [ '2023-01-10', 3 ] ]

Now i have this code that compare and combine these array manually

        let testData = [];
        let k = 0;
        dayList.forEach(o => {
            let is_match = 0;
            let frags = [];
            submitted.forEach(i => {
                if(o == i[0]){
                    is_match = 1;
                    frags = i;
                }
            });

            testData[k] = [
                (is_match == 1) ? frags[0] : o,
                (is_match == 1) ? frags[1] : 0
            ];

            k  ;
        });

        console.log(testData);

this will result to...

[
  [ '2022-12-11', 0 ], [ '2022-12-12', 0 ],
  [ '2022-12-13', 0 ], [ '2022-12-14', 0 ],
  [ '2022-12-15', 0 ], [ '2022-12-16', 0 ],
  [ '2022-12-17', 0 ], [ '2022-12-18', 0 ],
  [ '2022-12-19', 0 ], [ '2022-12-20', 0 ],
  [ '2022-12-21', 0 ], [ '2022-12-22', 0 ],
  [ '2022-12-23', 0 ], [ '2022-12-24', 0 ],
  [ '2022-12-25', 0 ], [ '2022-12-26', 0 ],
  [ '2022-12-27', 0 ], [ '2022-12-28', 0 ],
  [ '2022-12-29', 0 ], [ '2022-12-30', 0 ],
  [ '2022-12-31', 0 ], [ '2023-01-01', 0 ],
  [ '2023-01-02', 0 ], [ '2023-01-03', 0 ],
  [ '2023-01-04', 0 ], [ '2023-01-05', 0 ],
  [ '2023-01-06', 0 ], [ '2023-01-07', 0 ],
  [ '2023-01-08', 0 ], [ '2023-01-09', 1 ],
  [ '2023-01-10', 3 ], [ '2023-01-11', 0 ]
]

As you can see the date 2023-01-09 and 2023-01-10 have values then the rest has 0 values.

Which is what i expected, i'm just new in coding a pure javascript application, i just translated my PHP code to javascript.

Now is there a way that this code may be simplified using array functions of javascript or using lodash?

CodePudding user response：

You can simply run any loop and find the index of the current element in the submitted array and check if exist then assign date otherwise assign 0 to the array

var dayList = ['2022-12-11', '2023-01-10', '2023-01-09']
var submitted = [ [ '2023-01-09', 1 ], [ '2023-01-10', 3 ] ]
var testData = []
dayList.filter(o => {
    const exist = submitted.find(e => e.indexOf(o) != -1)
    if(exist){
        testData.push([o, exist[1]])
    } else {
        testData.push([o, 0])
    }
});
console.log("your data=", testData)

CodePudding user response：

Here's an approach, we first create a map with the date as key and count as value and then use this map to generate the result

const dates=["2022-12-11","2022-12-12","2022-12-13","2022-12-14","2022-12-15","2022-12-16","2022-12-17","2022-12-18","2022-12-19","2022-12-20","2022-12-21","2022-12-22","2022-12-23","2022-12-24","2022-12-25","2022-12-26","2022-12-27","2022-12-28","2022-12-29","2022-12-30","2022-12-31","2023-01-01","2023-01-02","2023-01-03","2023-01-04","2023-01-05","2023-01-06","2023-01-07","2023-01-08","2023-01-09","2023-01-10","2023-01-11",];

const count=[["2023-01-09",1],["2023-01-10",3]];

const countMap = count.reduce((acc, [date, count]) => {
    acc[date] = count;
    return acc;
}, {});

const result = dates.map((date) => [date, countMap[date] || 0]);

console.log(result)