Blather

Blather is a little js library for generating text with Markov chains.

A Simple Example

var Blather = require('blather');
 
var blatherer = Blather();
 
var fragments = [
    'I love dogs because they are fun',
    'I love cats because they are chill',
    'I wouldn\'t say I love snakes',
    'I do not care for ants',
    'Honestly, I hate snakes because they are disgusting and weird',
    'Zebras, because they live on a different continent than I do, I am indifferent towards',
    'I am a person with a lot of opinions about animals I love and don\'t love'
];
 
fragments.forEach(function(fragment) {
    blatherer.addFragment(fragment);
});
 
blatherer.generateFragment(); // 'I am a person with a lot of opinions about animals I love snakes'
blatherer.generateFragment(); // 'I wouldn't say I love dogs because they are fun'
blatherer.generateFragment(); // 'Honestly, I hate snakes because they are chill'

You get the picture. It mangles up the text. Accurately explaining Markov chains is beyond the scope of this README or my capabilities - I just use this to make silly toys and bots.

More Complicated Examples

Blather is pretty flexible in how it chews up your text fragments, and how it spits it back at you.

split

split is a function that takes a text fragment and splits it into distinct units. By default, it splits only on /\s+/, meaning those units are (roughly) words. If you wanted to get more fine-grained than that, though, you could do something like this:

var blatherer = Blather({
    split: function(text) {
        return text.split('');
    }
});

split takes a string and must return an array.

depth

depth controls how many units each step of the Markov generation looks at when determining what unit could possibly come next. By default, it's 2 - higher numbers mean a higher likelihood of exactly replicating source fragments, and lower numbers mean more chance for gibberish.

clean

clean is the last function a generated fragment passes through before coming out. It takes in an array of units and stitches them back together. By default, it just joins using a space, but imagine you were using the custom split defined above - you might want to do something like:

var blatherer = Blather({
    split: function(text) {
        return text.split('');
    },
    clean: function(textArray) {
        return textArray.join('');
    }
}
});

You could also shove custom cleanup logic here if you wanna get fancy - simple grammar checks, punctuation stripping, whatever. As long as it takes in an array of strings and returns a string, you're cool.

isStart

When adding fragments, Blather stores away certain groups of units as possible fragment-starters. If all your fragments are discrete units of language, like sentences or tweets, the default should do you fine - it just checks if it's the first group of units in the fragment. If you're adding paragraphs at a time, maybe you'd want something closer to this:

var blatherer = Blather({
    isStart: function(fragmentPiece, index) {
        return (fragmentPiece[0].toUpperCase() === fragmentPiece[0]);
    }
});

This would get you all the starts of sentences with capital letters (and all the proper nouns, too, which is a little sloppy), which might be useful. fragmentPiece is a string and index is the index of the piece within the fragment being added. The default function here just checks if index is zero.

joiner

This one's a little silly. If all is well, it shouldn't matter - it's just an implementation detail. As mentioned above, Blather is operating on arrays of units - as split by the split function and their length determined by depth - but it needs to turn those arrays into strings to use as object keys. joiner is the string it uses to join them.

By default, it is '<|>', but if that exact sequence of characters appears anywhere in your source fragments, it's gonna get fudged up. If you're doing weird things, try changing this, I guess - it really shouldn't be part of the public API, but I felt irresponsible leaving it out. Do what you will with this information.