pigx-wx-ui38/packages/mixins/bem.js

/**
 * bem helper
 * b() // 'button'
 * b('text') // 'button__text'
 * b({ disabled }) // 'button button--disabled'
 * b('text', { disabled }) // 'button__text button__text--disabled'
 * b(['disabled', 'primary']) // 'button button--disabled button--primary'
 */

const ELEMENT = '__';
const MODS = '--';

const join = (name, el, symbol) => el ? name + symbol + el : name;

const prefix = (name, mods) => {
    if (typeof mods === 'string') {
        return join(name, mods, MODS);
    }

    if (Array.isArray(mods)) {
        return mods.map(item => prefix(name, item));
    }

    const ret = {};
    Object.keys(mods).forEach(key => {
        ret[name + MODS + key] = mods[key];
    });
    return ret;
};

export default {
    methods: {
        b(el, mods) {
            const { name } = this.$options;

            if (el && typeof el !== 'string') {
                mods = el;
                el = '';
            }
            el = join(name, el, ELEMENT);

            return mods ? [el, prefix(el, mods)] : el;
        }
    }
};