index.js 1.2 KB

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  1. module.exports = function first(stuff, done) {
  2. if (!Array.isArray(stuff))
  3. throw new TypeError('arg must be an array of [ee, events...] arrays')
  4. var cleanups = []
  5. for (var i = 0; i < stuff.length; i++) {
  6. var arr = stuff[i]
  7. if (!Array.isArray(arr) || arr.length < 2)
  8. throw new TypeError('each array member must be [ee, events...]')
  9. var ee = arr[0]
  10. for (var j = 1; j < arr.length; j++) {
  11. var event = arr[j]
  12. var fn = listener(event, cleanup)
  13. // listen to the event
  14. ee.on(event, fn)
  15. // push this listener to the list of cleanups
  16. cleanups.push({
  17. ee: ee,
  18. event: event,
  19. fn: fn,
  20. })
  21. }
  22. }
  23. return function (fn) {
  24. done = fn
  25. }
  26. function cleanup() {
  27. var x
  28. for (var i = 0; i < cleanups.length; i++) {
  29. x = cleanups[i]
  30. x.ee.removeListener(x.event, x.fn)
  31. }
  32. done.apply(null, arguments)
  33. }
  34. }
  35. function listener(event, done) {
  36. return function onevent(arg1) {
  37. var args = new Array(arguments.length)
  38. var ee = this
  39. var err = event === 'error'
  40. ? arg1
  41. : null
  42. // copy args to prevent arguments escaping scope
  43. for (var i = 0; i < args.length; i++) {
  44. args[i] = arguments[i]
  45. }
  46. done(err, ee, event, args)
  47. }
  48. }