Angular Javascript object with arrays, looping through and getting length of each array?

Question

I'm trying to create a dataset from an API backend I've set up in my project. I've already managed to group my api call on the date but now I need to check the length of each date array that is created by lodash.

How would I do this because every attempt I've tried so far has failed. The image I've included shows the console.log after I have grouped my result, it also shows the amount of entries in each array which is exactly what I want to retrieve.

Current code, I removed my attempt at solving this problem because I would only get back undefined results.

        ngOnInit() {
        this._estimateService.getEstimates()
            .subscribe(estimateData => {
                const groupedEstimateData = groupBy(estimateData, 'estimate_date');
                console.log(groupedEstimateData);
            });
        }

Example of desired result:

2019-12-09, 47
2019-12-10, 6
etc

Image:

May you also post what you actually get from estimateData? — evolutionxbox
– evolutionxbox, Commented Jan 8, 2020 at 14:37

Benoit Messiaen · Accepted Answer · 2020-01-08 14:45:16Z

2

I'm not sure of what you mean by "checking the length". Here is an example of your desired console.log output

ngOnInit() {
        this._estimateService.getEstimates()
            .subscribe(estimateData => {
                const groupedEstimateData = groupBy(estimateData, 'estimate_date');
                Object.entries(groupedEstimatesData).map(([date, estimatedData]) => {
                    // do what you want there with each line
                    console.log(date, estimatedData.length);
                });
            });
        }

You can have a look at Object.entries and map methods.

Good luck

answered Jan 8, 2020 at 14:45

Benoit Messiaen

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1 Comment

Tolgon Over a year ago

Thanks for the Object.entries and map method suggestions. Your code worked perfectly.

Travis James · Accepted Answer · 2020-01-08 14:37:07Z

1

You could do something like:

const groupsWithCounts = Object.keys(groupedEstimateData).map(key => {
    [key]: groupedEstimateData[key],
    total: groupedEstimateData[key].length
})

Now groupsWithCounts will be an array of objects with this structure:

{
    2019-12-9: [item, item, item, ...], // the original items
    total: 47 // the total count of items
}

answered Jan 8, 2020 at 14:37

Travis James

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Comments

Jeremy Thille · Accepted Answer · 2020-01-08 14:44:13Z

1

You can do this simply with :

const dates = Object.keys(groupedEstimateData);

let output = {};

dates.forEach( date => output[date] = groupedEstimateData[date].length );

Object.keys(groupedEstimateData) will give you an array ["2019-12-09", "2019-12-10", etc]

You then iterate this array to construct this output object :

{
    "2019-12-09" : 47,
    "2019-12-10" : 6,
    etc
}

answered Jan 8, 2020 at 14:44

Jeremy Thille

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