24   const ev1 = common.mustCall(function(event) {  constant
36   eventTarget.addEventListener('foo', ev1);
43   eventTarget.removeEventListener('foo', ev1);
53   const ev1 = common.mustCall((event) => {  constant
63   strictEqual(eventTarget.on('foo', ev1), eventTarget);
70   strictEqual(eventTarget.off('foo', ev1), eventTarget);
80   const ev1 = common.mustCall((event) => {  constant
90   eventTarget.addListener('foo', ev1);
97   eventTarget.removeListener('foo', ev1);
108   const ev1 = () => {};  function
113   eventTarget.addListener('foo', ev1);
114   eventTarget.addEventListener('foo', ev1);
117   eventTarget.on('bar', ev1);