Class FrequencyTracker<V>

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).

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

Overview

const fh = new FrequencyTracker();
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 = new FrequencyTracker();
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 = 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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