classVarianceAuthority

/**
 * Simplified Class Variance Authority (CVA)
 *
 * Data structure:
 * - Nested object lookup table
 *
 * variants = {
 *   intent: {
 *     primary: 'btn-primary',
 *     secondary: 'btn-secondary',
 *   }
 * }
 *
 * Idea:
 * - Start with base classes
 * - Merge user variants with defaultVariants
 * - Lookup matching classes from variants map
 * - Join truthy classes with spaces
 *
 * @param {string | null | undefined} base
 * @param {Object} config
 * @returns {(props?: Object) => string}
 */
export default function cva(base, config = {}) {
  const {
    variants = {},
    defaultVariants = {},
  } = config;

  return function (props = {}) {
    const classes = [];

    // Add base class if truthy.
    if (base) {
      classes.push(base);
    }

    // Resolve final variant values:
    // user props override defaultVariants.
    const resolvedVariants = {
      ...defaultVariants,
      ...props,
    };

    // Iterate through known variants only.
    for (const variantName of Object.keys(variants)) {
      const variantMap = variants[variantName];

      const variantValue = resolvedVariants[variantName];

      // Variant keys in objects are strings.
      const className = variantMap[String(variantValue)];

      if (className) {
        classes.push(className);
      }
    }

    return classes.join(' ');
  };
}