3 const unique = arr => arr.filter((v, i) => arr.lastIndexOf(v) === i);
4 const compact = arr => unique(arr).filter(Boolean);
6 module.exports = (action, data = {}, value = '') => {
7 let { past = [], present = '' } = data;
13 rest = past.slice(0, past.length - 1);
14 prev = past[past.length - 1] || '';
16 past: compact([value, ...rest]),
25 past: compact([...rest, value]),
31 past: compact([...past, value]),
36 prev = compact(past.filter(v => v !== value));
49 throw new Error(`Invalid action: "${action}"`);