there is this

    if (er) cb(er)
    cb(null, cache[arg] = data)

did you mean this instead

    if (er) return cb(er)
    cb(null, cache[arg] = data)

Ryan Dahl, God among Gods, eschewed shorthand in favor of

    if (er) {
       return cb(er)
    }
    cb(null, cache[arg] = data)

For months i'm thinking how this can be done, even is it possible? Hm, don't know but i believe it is.

And I think that dezalgo is the right place for this.

previous discussion https://redd.it/59fvap

Last given snippet there works, but only if you does not use dezalgo (aka if not ensured that the callback is called in the next tick).

example

var once = require('once')
var dezalgo = require('dezalgo')

function task (fn) {
  var called = false
  function done (e) {
    called = true
    if (e) return console.log('err')
    console.log('ok')
  }

  fn(once(done))
  if (!called) console.log('callback is not called')
}

task(function (cb) {
  console.log('actual')
})
// signals that the `cb` is not called

But when we wrap the done with dezalgo we have a problem, logically. Because if it is called, it will be called in the next tick, so that if(!called) isn't in the correct time and the message is still outputed.

So such detection should be done in the dezalgo, because it calls the callback in the next tick. Or maybe in once.

i dont know what im doing wrong. i try install plugin in and suddenly this error come out. help me please. because i try so many thing. nothing help me. And it also make me cannot install any npm.

npm ERR! path /Users/.../.../.../.../node_modules/npm/node_modules/dezalgo/node_modules/asap
npm ERR! code ENOENT
npm ERR! errno -2
npm ERR! syscall rename
npm ERR! enoent ENOENT: no such file or directory, rename '/Users/.../.../.../.../node_modules/npm/node_modules/dezalgo/node_modules/asap' -> '/Users/.../.../.../.../node_modules/npm/node_modules/dezalgo/node_modules/.asap.DELETE'
npm ERR! enoent This is related to npm not being able to find a file.
npm ERR! enoent

im running on

$ node -v
v9.4.0
$ npm -v
5.6.0
$ ionic -v
3.19.0
$ cordova -v
8.0.0

Hi there!

When installing/updating a project of mine using npm install, I ran across the following problem with dezalgo:

npm ERR! enoent ENOENT: no such file or directory, rename '/Users/sander/Repositories/project/node_modules/npm/node_modules/dezalgo' -> '/Users/sander/Repositories/project/node_modules/npm/node_modules/.dezalgo.DELETE'
npm ERR! enoent This is related to npm not being able to find a file.

This seems to have occured out of the blue, so I wondered if this has anything to do with the dezalgo package?

Full debug log:

0 info it worked if it ends with ok
1 verbose cli [ '/usr/local/bin/node',
1 verbose cli   '/usr/local/bin/npm',
1 verbose cli   'i',
1 verbose cli   '--reinstall' ]
2 info using [email protected]
3 info using [email protected]
4 verbose npm-session 09a7132d3aa76b8c
[...]
15 silly idealTree [email protected]
15 silly idealTree ├─┬ [email protected]
15 silly idealTree │ ├── [email protected]
[...]
18 silly diffTrees add [email protected]
[...]
25 silly decomposeActions preinstall [email protected]
26 silly decomposeActions build [email protected]
27 silly decomposeActions install [email protected]
28 silly decomposeActions postinstall [email protected]
29 silly decomposeActions finalize [email protected]
30 silly decomposeActions refresh-package-json [email protected]
[...]
70 silly finalize /Users/sander/Repositories/project/node_modules/npm/node_modules/dezalgo
[...]
72 silly saveTree [email protected]
72 silly saveTree ├─┬ [email protected]
72 silly saveTree │ ├─┬ [email protected]
72 silly saveTree │ │ ├─┬ [email protected]
[...]
74 verbose stack Error: ENOENT: no such file or directory, rename '/Users/sander/Repositories/project/node_modules/npm/node_modules/dezalgo' -> '/Users/sander/Repositories/project/node_modules/npm/node_modules/.dezalgo.DELETE'
75 verbose cwd /Users/sander/Repositories/project
76 verbose Darwin 17.3.0
77 verbose argv "/usr/local/bin/node" "/usr/local/bin/npm" "i" "--reinstall"
78 verbose node v9.2.0
79 verbose npm  v5.6.0
80 error path /Users/sander/Repositories/project/node_modules/npm/node_modules/dezalgo
81 error code ENOENT
82 error errno -2
83 error syscall rename
84 error enoent ENOENT: no such file or directory, rename '/Users/sander/Repositories/project/node_modules/npm/node_modules/dezalgo' -> '/Users/sander/Repositories/project/node_modules/npm/node_modules/.dezalgo.DELETE'
85 error enoent This is related to npm not being able to find a file.
86 verbose exit [ -2, true ]

As you said in your blog:

This uses Node's synthetic deferral function: process.nextTick, which runs the supplied callback at the end of the current run-to-completion. You can also use setImmediate, but that's slightly slower. (Yes, yes, it's named badly; setImmediate is slightly less "immediate" and more "next" than nextTick, but this is an accident of history we cannot correct without a time machine.)

So, why in the implementation of this library to resolve the zalgo problem you prefer use asap library? Maybe for more crossover browser compatibility?