word frequency in javascript

Question

How can I implement javascript function to calculate frequency of each word in

Answer 1

Here is a JavaScript function to get the frequency of each word in a sentence:

function wordFreq(string) {
    var words = string.replace(/[.]/g, '').split(/\s/);
    var freqMap = {};
    words.forEach(function(w) {
        if (!freqMap[w]) {
            freqMap[w] = 0;
        }
        freqMap[w] += 1;
    });

    return freqMap;
}

It will return a hash of word to word count. So for example, if we run it like so:

console.log(wordFreq("I am the big the big bull."));
> Object {I: 1, am: 1, the: 2, big: 2, bull: 1}

You can iterate over the words with Object.keys(result).sort().forEach(result) {...}. So we could hook that up like so:

var freq = wordFreq("I am the big the big bull.");
Object.keys(freq).sort().forEach(function(word) {
    console.log("count of " + word + " is " + freq[word]);
});

Which would output:

count of I is 1
count of am is 1
count of big is 2
count of bull is 1
count of the is 2

JSFiddle: http://jsfiddle.net/ah6wsbs6/

And here is wordFreq function in ES6:

function wordFreq(string) {
  return string.replace(/[.]/g, '')
    .split(/\s/)
    .reduce((map, word) =>
      Object.assign(map, {
        [word]: (map[word])
          ? map[word] + 1
          : 1,
      }),
      {}
    );
}

JSFiddle: http://jsfiddle.net/r1Lo79us/