stylup.config.js

module.exports = {
    classes: [
        {
            name: 'spacing',
            class: ['p', 'm'],
            children: [
                't',
                'r',
                'b',
                'l'
            ],
            style({ rule, args, str }) {
                if (args) {
                    let values = args;

                    switch (values.length) {
                        case 1:
                            values.push(values[0]);
                        case 2:
                            values.push(values[0]);
                        case 3:
                            values.push(values[1]);
                    }

                    for (let [index, side] of rule.children.entries()) {
                        str`--${rule.class}${side}: ${values[index]};\n`
                    }

                    return str()
                }
            }
        },
        {
            name: 'colour',
            class: 'c',
            style({ rule, str }) {
                if (rule.args) {

                    str`--${rule.class}: ${rule.args[0]};\n`

                    return str()
                }
            }
        },
        {
            name: 'background color',
            class: 'bgc',
            style({ rule, str }) {
                if (rule.args) {

                    str`--${rule.class}: ${rule.args[0]};\n`

                    return str()
                }
            }
        },
        {
            name: 'width',
            class: 'w',
            style({ rule, str }) {
                if (rule.args) {
                    str`--${rule.class}: ${rule.args[0]};\n`

                    return str()
                }
            }
        },
    ]
}