Conditional Class using Object Representation

classs-with-string.js

export const classs = (...args) =>
  args
    .flatMap((object) =>
      object
        ? typeof object === "string"
          ? object
          : Object.entries(object).reduce(
              (str, [name, bool]) => (bool && name ? [...str, name] : str),
              []
            )
        : null
    )
    .filter((v) => v)
    .join(" ");


// Use case
const active = false;
const className = classs("test", {active, important: true });
console.log(className) // Output: "test important"

classs.js

const classs = (object) =>
  Object.entries(object).reduce(
    (str, [name, bool]) => `${str}${bool ? ` ${name}` : ""}`,
    ""
  );

const className = classs({active: clicked, important: true });
console.log(className)