Function isDeclared

lib/core/opts.js:27–29

(k)

  let handleOptionsMethod = defaults.handleOptionsMethod;

  function isDeclared(k) {
    return typeof opts[k] !== 'undefined' && opts[k] !== null;
  }

  function setHeader(str) {
    const m = /^(.+?)\s*:\s*(.*)$/.exec(str);