random.js•787 B
import { getMode } from './modes.js';
/*
Generate a random number between `min` and `max`
*/
const rand = ([min, max]) => min + Math.random() * (max - min);
/*
Convert a constraints object to intervals.
*/
const to_intervals = constraints =>
Object.keys(constraints).reduce((o, k) => {
let v = constraints[k];
o[k] = Array.isArray(v) ? v : [v, v];
return o;
}, {});
/*
Generate a random color.
*/
const random = (mode = 'rgb', constraints = {}) => {
let def = getMode(mode);
let limits = to_intervals(constraints);
return def.channels.reduce(
(res, ch) => {
// ignore alpha if not present in constraints
if (limits.alpha || ch !== 'alpha') {
res[ch] = rand(limits[ch] || def.ranges[ch]);
}
return res;
},
{ mode }
);
};
export default random;