Function frequency

Frequency keeps track of how many times a particular value is seen, but unlike a Map it does not store the data. By default compares items by value (via JSON.stringify).

Create with Trackers.frequency.

Fires change event when items are added or it is cleared.

Overview

const fh = Trackers.frequency();
fh.add(value); // adds a value
fh.clear();    // clears all data
fh.keys() / .values() // returns an iterator for keys and values
fh.toArray();  //  returns an array of data in the shape [[key,freq],[key,freq]...]
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Usage

const fh = Trackers.frequency();
fh.add(`apples`); // Count an occurence of `apples`
fh.add(`oranges)`;
fh.add(`apples`);

const fhData = fh.toArray(); // Expect result [[`apples`, 2], [`oranges`, 1]]
fhData.forEach((d) => {
 const [key,freq] = d;
 console.log(`Key '${key}' occurred ${freq} time(s).`);
})
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Custom key string

const fh = Trackers.frequency( person => person.name);
// All people with name `Samantha` will be counted in same group
fh.add({name:`Samantha`, city:`Brisbane`});
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