A close substitute for [colors.js](https://github.com/Marak/colors.js) in the browser. See https://jsfiddle.net/fbe4s9ry/ . Plan to move to https://github.com/brettz9/styled-log

colors.js

const colors = new Proxy({
    setTheme: function (theme) {
        this._theme = theme;
    },
    log: function (msgColor) {
        console.log(...msgColor);
    }
}, {
    get: function (target, name) {
        if (['setTheme', 'log', '_theme'].includes(name)) {
            return target[name];
        }
        const log = (/log/).test(name);
        name = log ? name.slice(3).toLowerCase() : name;
        let color = name;
        if (name in target._theme) {
            color = target._theme[name];
        }
        const ret = function (msg) {
            return ['%c' + msg, 'color: ' + color];
        };
        if (log) {
            return function (msgColor) {
                target.log(ret(msgColor));
            };
        }
        return ret;
    }
});

if (typeof module !== 'undefined') {
    module.exports = colors;
}

example.js

var theme = {
    pass: 'green',
    fail: 'red',
    timeout: 'red',
    notrun: 'red'
};
colors.setTheme(theme);

// Log "Good!" in green
colors.log(colors.pass('Good!'));
console.log(...colors.pass('Good!'));
colors.logPass('Good!');
colors.logGreen('Good!');

// Log "Bad!" in red
colors.log(colors.fail('Bad!'));
console.log(...colors.fail('Bad!'));
colors.logFail('Bad!');
colors.logRed('Bad!');