unleash.unleash/src/lib/services/state-util.js

const fs = require('fs');
const mime = require('mime');
const YAML = require('js-yaml');

const readFile = file =>
    new Promise((resolve, reject) =>
        fs.readFile(file, (err, v) => (err ? reject(err) : resolve(v))),
    );

const parseFile = (file, data) =>
    mime.getType(file) === 'text/yaml' ? YAML.safeLoad(data) : JSON.parse(data);

const filterExisting = (keepExisting, existingArray = []) => item => {
    if (keepExisting) {
        const found = existingArray.find(t => t.name === item.name);
        return !found;
    }
    return true;
};

const filterEqual = (existingArray = []) => item => {
    const toggle = existingArray.find(t => t.name === item.name);
    if (toggle) {
        return JSON.stringify(toggle) !== JSON.stringify(item);
    }
    return true;
};

module.exports = {
    readFile,
    parseFile,
    filterExisting,
    filterEqual,
};