index.js

const regexp =
  /((?<k1>(?!=)\S+)=((?<v1>(["'`])(.*?)\5)|(?<v2>\S+)))|(?<k2>\S+)/g;

export function parse(string) {
  const io = (string ?? '').matchAll(regexp);

  return new Map(
    [...io]
      .map((item) => item?.groups)
      .map(({ k1, k2, v1, v2 }) => [k1 ?? k2, v1 ?? v2]),
  );
}

export function stringify(object) {
  return (
    object instanceof Map ? [...object.entries()] : Object.entries(object)
  )
    .map(([k, v]) => [k, v].filter((i) => i !== undefined).join('='))
    .join(' ');
}

export function getValue(string) {
  return string?.match?.(/(["'`])(?<value>.*?)\1/)?.groups?.value ?? string;
}